ACPAtmospheric Chemistry and PhysicsACPAtmos. Chem. Phys.1680-7324Copernicus PublicationsGöttingen, Germany10.5194/acp-19-861-2019Effects of Arctic stratospheric ozone changes on spring precipitation in the
northwestern United StatesEffects of ASO on precipitation in the northwestern USMaXuanXieFeixiefei@bnu.edu.cnLiJianpinghttps://orcid.org/0000-0003-0625-1575ZhengXinlongTianWenshouDingRuiqiangSunChenghttps://orcid.org/0000-0003-0474-7593ZhangJiankaiCollege of Global Change and Earth System Science, Beijing Normal University, Beijing, ChinaLaboratory for Regional Oceanography and Numerical Modeling, Qingdao National
Laboratory for Marine Science and Technology, Qingdao, ChinaCollege of Atmospheric Sciences, Lanzhou University, Lanzhou, ChinaState Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, ChinaFei Xie (xiefei@bnu.edu.cn)23January201919286187525April20187June20184December201820December2018This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/This article is available from https://acp.copernicus.org/articles/19/861/2019/acp-19-861-2019.htmlThe full text article is available as a PDF file from https://acp.copernicus.org/articles/19/861/2019/acp-19-861-2019.pdf
Using observations and reanalysis, we find that changes in April
precipitation variations in the northwestern US are strongly linked to March
Arctic stratospheric ozone (ASO). An increase in ASO can result in enhanced
westerlies in the high and low latitudes of the North Pacific but weakened
westerlies in the midlatitudes. The anomalous circulation over the North
Pacific can extend eastward to western North America, decreasing the water
vapor concentration in the air over the northwestern United States and
enhancing downwelling in the northwestern US, which results in decreased
precipitation there and vice versa for the decrease in ASO. Model
simulations using the Whole Atmosphere Community Climate Model version 4 (WACCM4) support the statistical analysis of observations and
reanalysis data and further reveal that the ASO influences circulation
anomalies over the northwestern US in two ways. Stratospheric circulation
anomalies caused by the ASO changes can propagate downward to the troposphere
in the North Pacific and then eastward to influence the strength of the
circulation anomalies over the northwestern US. In addition, sea surface
temperature anomalies over the North Pacific, which may be related to the ASO
changes, would cooperate with the ASO changes to modify the circulation
anomalies over the northwestern US. Our results suggest that ASO variations
could be a useful predictor of spring precipitation changes in the
northwestern US.
Introduction
Stratospheric circulation anomalies can affect tropospheric climate via
chemical–radiative–dynamical feedback processes (Baldwin and Dunkerton,
2001; Graf and Walter, 2005; Cagnazzo and Manzini, 2009; Ineson and Scaife,
2009; Thompson et al., 2011; Reichler et al., 2012; Karpechko et al., 2014;
Kidston et al., 2015; Li et al., 2016; Zhang et al., 2016; Wang et al.,
2017). Since stratospheric ozone can influence stratospheric temperature and
circulation via the atmospheric radiation balance (Tung, 1986; Haigh, 1994;
Ramaswamy et al., 1996; Forster and Shine, 1997; Pawson and Naujokat, 1999;
Solomon, 1999; Randel and Wu, 1999, 2007; Labitzke and Naujokat, 2000;
Gabriel et al., 2007; Gillett et al., 2009; McCormack et al., 2011), the impact
of ozone on tropospheric climate change has recently received widespread
attention (e.g., Nowack et al., 2015, 2017, 2018).
In recent decades, Antarctic stratospheric ozone has decreased dramatically
due to the increase in anthropogenic emissions of ozone-depleting substances
(Solomon, 1990, 1999; Ravishankara et al., 1994, 2009). Numerous studies
have found that the decreased Antarctic ozone has contributed substantially
to climate change in the Southern Hemisphere. The Southern Hemisphere
circulation underwent a marked change during the late 20th century, with a
slight poleward shift of the westerly jet (Thompson and Solomon, 2002;
Archer and Caldeira, 2008). The poleward circulation shift would cause
surface temperature anomalies by affecting localized wind patterns and
associated thermal advection (Son et al., 2010; Thompson et al., 2011;
Feldstein, 2011). Subsequent studies concluded that Antarctic ozone
depletion is responsible for at least 50 % of the circulation shift (Lu et
al., 2009; Son et al., 2010; McLandress et al., 2011; Polvani et al., 2011;
Hu et al., 2013; Gerber and Son, 2014; Waugh et al., 2015). In addition, the
poleward displacement of the westerly jet has been linked to an extension of
the Hadley cell (Son et al., 2009, 2010; Min and Son, 2013) and variations
in mid- to high-latitude precipitation during austral summer, i.e.,
increased rainfall in the subtropics and high latitudes and reduced rainfall
in the midlatitudes of the Southern Hemisphere (Son et al., 2009;
Feldstein, 2011; Kang et al., 2011; Polvani et al., 2011). The changes in
Antarctic ozone are not only related to the displacement of the westerly jet
in the Southern Hemisphere but also affect its intensity. Thompson and
Solomon (2002) argued that Antarctic ozone depletion can also enhance
westerly winds via the strong radiative cooling effect and thermal wind
relationship. The westerly winds are enhanced from the stratosphere to the
midlatitude troposphere in the case of wave–mean flow interaction (Son et
al., 2010; Thompson et al., 2011), thereby accelerating circumpolar currents
in the midlatitudes. Moreover, changes in subtropical drought, storm tracks
and ocean circulation in the Southern Hemisphere are also closely related to
Antarctic ozone variations (Yin, 2005; Russell et al., 2006; Son et al.,
2009; Polvani et al., 2011; Bitz and Polvani, 2012).
The variations in Arctic stratospheric ozone (ASO) in the past 5 decades
are quite different from those of Antarctic stratospheric ozone, as the
multi-decadal loss of ASO is much smaller than that of Antarctic
stratospheric ozone (WMO, 2011). However, sudden stratospheric warming in
the Arctic (Randel, 1988; Charlton and Polvani, 2007; Manney et al., 2011;
Manney and Lawrence, 2016) means that the year-to-year variability in ASO
has an amplitude equal to or even larger than that of Antarctic
stratospheric ozone. Thus, the effect of ASO on Northern Hemisphere climate
change has also become a matter of concern.
Similar to the effects of winter stratospheric dynamical processes on the
tropospheric North Atlantic Oscillation and the incidence of extreme weather
events (Baldwin and Dunkerton, 2001; Black et al., 2005, 2006, 2009), the
depletion of spring ASO can cause circulation anomalies that influence the
tropospheric North Atlantic and North Pacific sectors. Cheung et al. (2014)
used the UK Met Office operational weather forecasting system, and Karpechko
et al. (2014) used ECHAM5 simulations to investigate the relationship
between extreme Arctic ozone anomalies in 2011 and tropospheric climate.
Smith and Polvani (2014) used an atmospheric global climate model to reveal
a significant influence of ASO changes on tropospheric circulation, surface
temperature and precipitation when the amplitudes of the forcing ASO
anomaly in the model are larger than those historically observed.
Subsequently, using a fully coupled chemistry–climate model, Calvo et
al. (2015) again confirmed that changes in ASO can produce robust anomalies in
Northern Hemisphere temperature, wind and precipitation. Furthermore, the
effects of ASO on the Northern Hemisphere climate can be seen in
observations. Ivy et al. (2017) presented observational evidence for the
relationship between ASO and tropospheric climate, revealing that the
maximum daily surface temperature anomalies in spring (March–April) in some
regions of the Northern Hemisphere occurred during years with low ASO in
March. Xie et al. (2016, 2017a, b) demonstrated that the tropical
climate can also be affected by ASO. They pointed out that stratospheric
circulation anomalies caused by March ASO changes can rapidly extend to the
lower troposphere and then propagate horizontally to the North Pacific in
about 1 month, influencing the North Pacific sea surface temperature (SST)
in April. The induced SST anomalies (Victoria Mode) associated with the
circulation anomalies can influence El Niño–Southern Oscillation (ENSO)
and tropical rainfall over a timescale of ∼20 months.
Correlation coefficients between March ASO and April precipitation
variations calculated from SWOOSH (a, b) and GOZCARDS (c, d) ozone, and GPCC
(a, c) and GPCP (b, d) rainfall for the period 1984–2016. Dots denote
significance at the 95 % confidence level, according to Student's t test.
The long-term linear trend and seasonal cycle in all variables were removed
before the correlation analysis.
The Community Earth
System Model (CESM) WACCM4 experiments with various specified ozone and SST
forcing.
Exp1Specified ozone and SST forcingOther forcingR1Time-slice run, like the control experiment, used case F_2000_WACCM_SC. The specified ozone forcing is a 12-month cycle of monthly ozone averaged from 1995 to 2005. The specified SST forcing is a 12-month cycle of monthly SST averaged from 1995 to 2005.Fixed solar constant, fixed GHG values (averages of emissions scenario A2 of the Intergovernmental Panel on Climate Change – WMO, 2003 – over the period 1995–2005), volcanic aerosols (from the Stratospheric Processes and their Role in Climate – SPARC – Chemistry–Climate Model Validation – CCMVal – REF-B2 scenario recommendations) and QBO phase signals with a 28-month zonal wind fixed cycle.R2Same as R1, except that the March ozone in the region 30–90∘ N at 300–30 hPa2 is decreased by 15 % compared with R1.Same as R1R3Same as R1, except that March ozone in the region 30–90∘ N at 300–30 hPa is increased by 15 % compared with R1.Same as R1R4Same as R2, except that SST anomalies in the region 0–70∘ N and 120∘ E–90∘ W related to negative ASO anomalies3 are added in the SST forcing in April.Same as R1R5Same as R3, except that SST anomalies in the region 0–70∘ N and 120∘ E–90∘ W related to positive ASO anomalies4 are added in the SST forcing in April.Same as R1R6Same as R1, except that SST anomalies in the region 0–70∘ N and 120∘ E–90∘ W related to negative ASO anomalies3 are added in the SST forcing in April.Same as R1R7Same as R1, except that SST anomalies in the region 0–70∘ N and 120∘ E–90∘ W related to positive ASO anomalies4 are added in the SST forcing in April.Same as R1R8Transient run using case B_1955–2005_WACCM_SC_CN in CESM. E1 is a historical simulation covering the period 1955–2005. Note that the specified ozone forcing for 1955–2005 was derived from the CMIP5 ensemble mean ozone output. The specified ozone forcing was named ghg_forcing_1955–2005_CMIP5_EnsMean.c140414.nc and can be downloaded at https://svn-ccsm-inputdata.cgd.ucar.edu/trunk/inputdata/atm/waccm/ub/ghg_forcing_1955-2005_CMIP5_EnsMean.c140414.nc (last access: 19 November 2018).All natural and anthropogenic external forcings for R8 are based on observation and from original CESM input data.
1 Integration time for time-slice runs is 33 years and is 51 years for
transient run.
2 To avoid the effect of the boundary of ozone change on the Arctic
stratospheric circulation simulation, the replaced region (30–90∘ N,
300–30 hPa) was larger than the region used to define
the ASO index (60–90∘ N, 100–50 hPa).
3 For SST anomalies, see Fig. 9a.
4 For SST anomalies, see Fig. 9b.
As shown above, a large number of observations and simulations have shown
that ASO variations have a significant impact on Northern Hemisphere
tropospheric climate, but few studies have focused on regional
characteristics. Xie et al. (2018) found that the ASO variations could
significantly influence rainfall in the central China, since the circulation
anomalies over the North Pacific caused by ASO variations can extend
westward to China. This motivates us to investigate whether the circulation
anomalies extend eastward to affect the precipitation in North America. In
this study, we find a strong link between ASO and precipitation in the
northwestern US in spring. We focus on analyzing the characteristics of the
impact of ASO on precipitation in the northwestern US in spring and the
associated mechanisms. The remainder of this paper is organized as
follows. Section 2 describes the data and numerical simulations, and Sect. 3
discusses the relationship between the ASO anomalies and precipitation
variations in the northwestern US, as well as the underlying mechanisms. The
results of simulations are presented in Sect. 4, and conclusions are given
in Sect. 5.
(a) Correlation coefficients between March ASO index and
precipitation anomalies in the northwestern US (43–50∘ N,
115–130∘ W) for each month
calculated from SWOOSH (a, b) and GOZCARDS (c, d) ozone, and GPCC (a, c) and
GPCP (b, d) rainfall for the period 1984–2016. The dashed black lines
refer to the correlation coefficient that is significance at 95 %
confidence level. The long-term linear trend and seasonal cycle were removed
from the original datasets before calculating the correlation coefficients.
Data and simulations
The ASO variations are defined as the Arctic stratospheric ozone averaged
over the latitude of 60–90∘ N at an altitude of
100–50 hPa after removing the seasonal cycle and trend. Ozone values used
in the present analysis are derived from the Stratospheric Water and OzOne
Satellite Homogenized (SWOOSH) dataset (Davis et al., 2016), which is a
collection of stratospheric ozone and water vapor measurements obtained by
multiple limb-sounding and solar-occultation satellites over the previous 30
years. Monthly mean ozone data from SWOOSH (1984–2016) form a zonal-mean
gridded dataset at a horizontal resolution of 2.5∘ (latitude:
89∘ S to 89∘ N) and vertical pressure range of 31 levels
from 316 to 1 hPa. Another set of ozone data is taken from Global OZone
Chemistry And Related trace gas data records for the Stratosphere (GOZCARDS,
1984–2013) project (Froidevaux et al., 2015), based on high-quality data
from past missions (e.g., the Stratospheric Aerosol and Gas Experiment – SAGE – and the Halogen Occultation Experiment – HALOE – data) and ongoing missions (ACE-FTS
and Aura MLS). It is also a zonal-mean dataset with a meridional resolution
of 10∘, extending from the surface to 0.1 hPa (25 levels).
In addition, two sets of global precipitation reanalysis datasets are
employed in this study: monthly mean precipitation data constructed by the
Global Precipitation Climatology Project (GPCP), which is established by the
World Climate Research program (WCRP) in 1986 aiming to observe and estimate
the spatial and temporal global precipitation (Huffman et al., 1997), with a latitude and longitude
grid with a resolution of 2.5∘ for the analysis period
1984–2016; global terrestrial rainfall dataset derived from the Global
Precipitation Climatology Centre (GPCC) based on quality-controlled data
from 67 200 stations worldwide, with a resolution of 1.0∘
latitude/longitude grid. In addition, SST is taken from the UK Met Office
Hadley Centre for Climate Prediction and Research SST (HadSST; Rayner et
al., 2003). Other atmospheric datasets including monthly mean wind and
vertical velocity fields for the period 1984–2016 are obtained from the
NCEP – Department of Energy (DOE) Reanalysis 2 (NCEP-2) project, regarded as an
updated NCEP and National Center for Atmospheric Research's (NCAR) Reanalysis Project (NCEP-1).
We use the Whole Atmosphere Community Climate Model version 4 (WACCM4), a
part of the National Center for Atmospheric Research (NCAR) Community Earth
System Model (CESM), version 1.0.6, to investigate precipitation response in
the northwestern United States to the ASO anomalies. WACCM4 encompasses the
Community Atmospheric Model version 4 (CAM4) and as such includes all of its
physical parameterizations (Neale et al., 2013). It uses a system made up of
four components, namely atmosphere, ocean (specified SST), land and sea ice
(Holland et al., 2012) and has detailed mid-atmosphere chemistry. This
improved version of WACCM uses a finite-volume dynamical core, and it
extends from the surface to an approximately 145 km geometric altitude (66
levels), with a vertical resolution of about 1 km in the tropical tropopause
layer and the lower stratosphere. Note that the simulations in the present
paper are without interactive chemistry like the WACCM4 greenhouse-gas (GHG) scheme (WACCM4-GHG; Garcia et al.,
2007), with a 1.9∘× 2.5∘ horizontal resolution.
In the WACCM4-GHG, the chemistry is specified in this scheme, i.e., the volume
mixing ratios of forcings such as O3, CO2, CH4, N2O,
CFC11 and CFC12 are
prescribed in WACCM4-GHG (Marsh et al., 2013). The model's radiation scheme
uses these conditions: fixed GHG values (averages of
emissions scenario A2 of the Intergovernmental Panel on Climate Change – WMO,
2003 – over the period 1995–2005). The prescribed ozone forcing used in the
experiments is a 12–month seasonal cycle averaged over the period
1995–2005 from CMIP5 ensemble mean ozone output. The quasi-biennial
oscillation (QBO) phase signals with a 28–month fixed cycle are included in
WACCM4 as an external forcing for zonal wind.
Seven time-slice experiments (R1–R7) and a transient experiment with
specified ozone (R8) are designed to investigate the precipitation changes
in the northwestern US due to the ASO anomalies. Details of the eight
experiments are given in Table 1. Seven time-slice experiments (R1–R7) are
run for 33 years, with the first 3 years excluded for the model spin-up, and
only the last 30 years are used. The transient experiment (R8) is run
for 51 years.
Correlation coefficients between March ASO index and April zonal
wind variations (m s-1; from NCEP-2) from 1984 to 2016 at 200 hPa (a), 500 hPa
(b) and 850 hPa (c). Dots denote significance at the 95 % confidence
level, according to Student's t test. Blue square is the area shown in Fig. 1.
Before performing the analysis, the seasonal cycle and linear trend were
removed from the original datasets.
Differences in composite April winds (vectors, m s-1; from NCEP-2)
between positive and negative ASO anomaly events at 200 hPa (a), 500 hPa
(b) and 850 hPa (c) for 1984–2016. Colored regions are statistically
significant at the 90 % (light yellow) and 95 % (dark yellow) confidence
levels. The seasonal cycle and linear trend were removed from the original
dataset. The ASO anomaly events are selected based on Table 2.
(a) Longitude–latitude cross section of differences in composite
April vertical velocity anomalies (averaged over 1000–500 hPa) between
positive and negative ASO anomaly events for 1984–2016. (b)
Longitude–height cross section of differences in composite April vertical
velocity anomalies (averaged over 43–50∘ N) between
positive and negative ASO anomaly events from 1984 to 2016. Blue is upward
motion, and red is downward motion. Dots denote significance at the 95 %
confidence level. Before performing the analysis, the seasonal cycle and
linear trend were removed from the original dataset. The ASO anomaly events
are selected based on Table 2. The vertical velocity (Pa s-1) dataset is from
NCEP-2.
Response of precipitation in the northwestern US to ASO anomalies in
spring
Since the variations in ASO are most obvious in March due to the Arctic
polar vortex breakdown (Manney et al., 2011), previous studies have
reported that the ASO changes in March have the strongest influence on the
Northern Hemisphere (Ivy et al., 2017; Xie et al., 2017a). In addition,
these studies pointed out that the changes in ASO affect the tropospheric
climate with a lead of about 1–2 months, which is similar to the
troposphere response to the Northern Hemisphere sudden stratospheric
warmings (Baldwin and Dunkerton, 2001; Black et al., 2005, 2006, 2009) and
Southern Hemisphere stratospheric ozone depletion (Thompson and Solomon
2002); the relevant mechanisms have been investigated in detail by Xie et
al. (2017a). In Fig. 1, we therefore show the correlation coefficients
between ASO variations in March from SWOOSH and GOZCARDS data and
precipitation anomalies in April from GPCC and GPCP data over western North
America. In all cases in Fig. 1, the March ASO changes are significantly
anticorrelated with April precipitation anomalies in the northwestern US
(mainly in Washington and Oregon), implying that positive spring ASO
anomalies are associated with less spring precipitation in the northwestern
US and vice versa for the negative spring ASO anomalies. Note that since
this kind of feature appears in the northwestern US, Fig. 1 shows only the
western side of North America.
(a) Spatial distribution of April precipitation (mm day-1)
climatology in the control experiment (R1). (b) Same as (a), but
precipitation from the GPCP for the period 1995–2005. For details of
specific experiments, see Table 1.
The correlation coefficients between March ASO variations and precipitation
anomalies (January to December are in the same year) in the northwestern US
are shown in Fig. 2. The correlation coefficients between March ASO
variations and April precipitation anomalies in the northwestern US are the
largest and are significant at the 95 % confidence level. Note that the
correlation coefficients between March ASO variations and July precipitation
anomalies are also significant. The impact of March ASO on precipitation in
the northwestern US in summer and the associated mechanisms are different
from those considered in this study (not shown) and will be presented in
another paper but will not be investigated further here. March ASO changes
are not significantly correlated with simultaneous (March) precipitation
variations (Fig. 2), illustrating that the ASO changes lead precipitation
anomalies by about 1 month. Since the results from four sets of observations
show a common feature, and SWOOSH and GPCP data span a longer period, only
SWOOSH ozone and GPCP precipitation are used in the following analysis.
The above statistical analysis shows a strong negative correlation between
March ASO variations and April precipitation anomalies in the northwestern
US, meaning that the ASO can be used to predict changes in spring
precipitation in the northwestern US. The process and underlying mechanism
that are responsible for the impact of ASO anomalies on precipitation
changes need further analysis.
Differences between experiments R3 and R2 in terms of April (a)
precipitation (mm day-1) and (b–d) zonal wind at 200, 500 and 850 hPa,
respectively. Dots denote significance at the 95 % confidence level.
Figure 3 shows the correlation coefficients between March ASO anomalies and
April zonal wind variations at 200, 500 and 850 hPa, respectively. The
spatial distribution of significant correlation coefficients over the North
Pacific exhibits a tripolar mode with a zonal distribution at 200 and
500 hPa; i.e. a positive correlation in the high and low latitudes in the North
Pacific and a negative correlation in midlatitudes. This implies that the
increase in ASO can result in enhanced westerlies in the high and low
latitudes of the North Pacific but weakened westerlies in the midlatitudes,
corresponding to the weakened Aleutian Low in April and vice versa for the
decrease in ASO. The Aleutian Low acts as a bridge connecting variations in
ASO and circulation anomalies over the North Pacific (Xie et al., 2017a). At
850 hPa, the anomalous circulation signal in the low latitudes of the North
Pacific has weakened and disappeared. It is evident that the anomalous
changes in the zonal wind over the North Pacific can extend westward to East
Asia. Xie et al. (2018) identified the effect of spring ASO changes on
spring precipitation in China. Note that the weakened westerlies in the
midlatitudes and the enhanced westerlies at low latitudes can also extend
eastward to the western United States. This kind of circulation anomaly
corresponds to two barotropic structures, i.e., an anomalous anticyclone in
the Northeast Pacific and a cyclone in the southwestern United States at
500 and 200 hPa. Coincidentally, the northwestern United States is located
to the north of the intersection of the anticyclone and cyclone,
corresponding to convergence of the airflow at high levels, which may lead
to downwelling in the northwestern United States and vice versa for
negative March ASO anomalies.
To further validate our inference regarding the response of the circulation
in the western United States to ASO changes, we analyze the differences
between April horizontal wind anomalies during positive and negative March
ASO anomaly events at 200, 500 and 850 hPa (Fig. 4). As in the increased
ASO case, the difference shows an anomalous anticyclone in the Northeast
Pacific and an anomalous cyclone in the southwestern United States. The
climatological wind over the northwestern United States blows from west to
east, bringing moisture from the Pacific to the western United States. Such
circulation anomalies force an anomalous cyclone in the western United
States in the middle and upper troposphere, which reduces the climatological
wind. It would decrease the water vapor concentration in the air over the
northwestern United States. In addition, the northwestern United States is
located to the north of the intersection of the anticyclone and cyclone,
suggesting downwelling flow in the region.
(a) Correlation coefficients between regional precipitation
(43–50∘ N, 115–130∘ W) and SST
variations in April for 1984–2016. (b) Correlation coefficients between
March ASO (ASO multiplied by -1) and April SST variations for 1984–2016. Dots
denote significance at the 95 % confidence level, according to Student's
t test. Before performing the analysis, the seasonal cycle and linear trend
were removed from the original data. ASO data are from SWOOSH, precipitation
from GPCP and SST from HadSST.
Figure 5a shows a longitude–latitude cross section of differences in April
vertical velocity anomalies averaged over 1000–500 hPa between positive and
negative March ASO anomaly events. When the March ASO increases, anomalous
downwelling is found in the northwestern United States
(115–130∘ W). This situation may inhibit precipitation in the
northwestern United States in April. Figure 5b depicts the longitude–height
cross section of differences in April vertical velocity averaged over
43–50∘ N between positive and negative March ASO
anomaly events, which further shows an anomalous downwelling over the
northwestern United States when the ASO increases. Based on the above
analysis, the circulation anomalies in the northwestern United States
associated with positive March ASO anomalies may inhibit the formation of
local precipitation in April and vice versa for that with negative March
ASO anomalies.
Simulations of the effect of ASO variations on precipitation in the
northwestern US during spring
Using observations and reanalysis data, we investigated the relationship
between March ASO and April precipitation in the northwestern US and
revealed the underlying mechanisms in Sect. 3. In this section, we use
WACCM4 simulations (see Sect. 2) to confirm the above conclusions. First,
we check the model performance in simulating precipitation over western
North America. Figure 6 shows the April precipitation climatology over the
region 95–140∘ W, 30–63∘ N
from the control experiment R1 (Table 1) and from GPCP for the period
1995–2005. The model simulates a center of high precipitation over the West
Coast of North America (Fig. 6a). It is clear that the spatial distribution
of the simulated precipitation climatology is similar to that calculated by
GPCP (Fig. 6b).
(a) Composite SST anomalies during negative ASO anomaly events.
(b) Composite SST anomalies during positive ASO anomaly events. The ASO
anomaly events are selected based on Table 2. SST data are from CESM SST
forcing data.
Figure 7a displays the differences in April precipitation between
experiments R3 and R2. The pattern of simulated April precipitation
anomalies forced by ASO changes in western North America (Fig. 7a) is
different from that observed (Fig. 1), i.e., the increased March ASO forces
an increase in precipitation in the northwestern United States. The
differences in April zonal wind at 200, 500 and 850 hPa between experiments
R3 and R2 are shown in Fig. 7b, c and d, respectively. The simulated
pattern of April zonal wind anomalies in western North America (Fig. 7b, c
and d) shifted a little further to the north than in the observations
(Fig. 3). Comparing the global pattern of simulated April zonal wind anomalies
with the observations, it is surprising to find that the positions of
simulated zonal wind anomalies over the Northeast Pacific and western North
America are shifted northward. This results in the simulated precipitation
anomalies over western North America also shifting northward so that a
decrease in precipitation on the western coast of Canada in April is found in
Fig. 7a. This explains why we find that the pattern of simulated April
precipitation anomalies in the North America (Fig. 7a) is nearly opposite to
that observed (Fig. 1). Figure 7 shows that the results of the model
simulation in which we only change the ASO forcing do not reflect the real
situation of April precipitation anomalies in the northwestern United
States, with a shift in position compared with observations. This leads us
to consider whether other factors interact with March ozone to influence
April precipitation in the northwestern United States.
Same as Fig. 7, but for the difference between experiments R5
and R4.
Same as Fig. 7, but for the difference between experiments R7
and R6.
Previous studies have found that the North Pacific SST has a significant
effect on precipitation in the United States (e.g., Namias, 1983; Ting and
Wang, 1997; Wang and Ting, 2000; Barlow et al., 2001; Lau et al., 2002; Wang
et al., 2014). Figure 8a shows the correlation coefficients between regional
averaged (43–50∘ N, 115–130∘ W) precipitation
anomalies and SST variations in April. Interestingly, the
results show that the distribution of correlation coefficients over the
North Pacific has a meridional tripole structure, which is referred to as
the Victoria-mode SST anomaly pattern. Xie et al. (2017a) demonstrated that
the ASO has a lagged impact on the sea surface temperature in the North
Pacific mid-to-high latitudes based on observation and simulation. They showed
that stratospheric circulation anomalies caused by ASO changes can rapidly
extend to the lower troposphere in the high latitudes of the Northern
Hemisphere. The circulation anomalies in the high latitudes of the lower
troposphere take about a month to propagate to the North Pacific
midlatitudes and then influence the North Pacific SST. Figure 8b shows the
correlation coefficients between March ASO (multiplied by -1) and April SST
variations. The pattern in Fig. 8b is in good agreement with that in
Fig. 8a. It is further found that removing the Victoria-mode signal from the time
series of precipitation in the northwestern United States reduces the
correlation coefficient between March ASO anomalies and filtered April
precipitation variations in the northwestern United States to -0.40 (the
correlation coefficient is -0.55 for the original time series; see Fig. 2),
but it remains significant. Figure 8 indicates that the ASO possibly
influences precipitation anomalies in the northwestern United States in two
ways. First, the stratospheric circulation anomalies caused by the ASO
changes can propagate downward to the North Pacific troposphere and eastward
to influence precipitation over northwestern United States. Second, the ASO
changes generate SST anomalies over the North Pacific that act as a bridge
for ASO to affect precipitation in the northwestern United States (Xie et
al., 2017a). The SST anomalies caused by ASO change likely interact with the
direct changes in atmospheric circulation driven by the ASO change to
jointly influence precipitation in the northwestern United States.
Experiments R2 and R3 do not include the effects of SST, which may explain
why the results of the model simulation in which we only change the ASO
forcing do not reflect the observed precipitation anomalies in the
northwestern United States (Fig. 7).
Correlation coefficients between the specified March ASO
variations and simulated anomalies of April U (a), SST (b) and
precipitation (c) for the period 1955–2005, based on the transient
experiment R8. Regions above the 95 % confidence level are dotted. The
seasonal cycle and linear trend were removed from all quantities before
correlation.
Selected positive and negative years for March ASO anomaly events
based on SWOOSH data for the period 1984–2016. Positive and negative March
ASO anomaly events are defined using a normalized time series of March ASO
variations from 1984 to 2016. Values larger than 1 standard deviation are
defined as positive March ASO anomaly events, and those below -1 standard
deviation are defined as negative March ASO anomaly events.
Positive March ASONegative March ASOanomaly eventsanomaly events1998, 1999, 2001, 2004, 20101993, 1995, 1996, 2000, 2011
Two sets of experiments (R4 and R5) that include the joint effects of ASO
and SST changes (Fig. 9) are added. Details of the experiments are given in
Table 1. Figure 10 shows the differences in April precipitation and zonal
wind between experiments R5 and R4. It is clear that the simulated changes
in precipitation in the northwestern United States (Fig. 10a) are in good
agreement with the observed anomalies shown in Fig. 1, i.e., the increase in
March ASO forces a decrease in April precipitation in the northwestern
United States. In addition, the spatial distributions of simulated zonal
wind anomalies (Fig. 10b–d) are consistent with the observations (Fig. 3).
Overall, the simulated precipitation and circulation in R4 and R5 are no
longer shifted northward and are closer to the observations.
To further emphasize the importance of the joint effects of ASO and
ASO-related SST anomalies on precipitation in the northwestern United
States, we investigate whether the spring Victoria-mode-like SST anomalies
alone could force the observed precipitation anomalies in the northwestern
United States. Two sets of experiments are performed here (R6 and R7), in
which only April SST anomalies over the North Pacific have been changed
(Fig. 9). Details of the experiments are given in Table 1. Figure 11 shows
the differences in April precipitation and zonal wind between experiments R7
and R6. The simulated precipitation anomalies over the West Coast of the
United States (Fig. 11a) are much weaker, and the simulated circulation
anomalies (Fig. 11b–d) are quite different from those in Fig. 3. This
suggests that the ASO-related North Pacific SST anomalies alone cannot force
the observed precipitation anomalies in the northwestern United States but
that the combined effect of ASO and ASO-related North Pacific SST anomalies
is required (Fig. 10).
(a) Correlation coefficients between the index of February SPV
multiplied by -1 (105 K m2 kg-1 s-1) defined by Zhang et al. (2018) and April
zonal wind variations at 200 hPa for 1984–2016. (b) Correlation
coefficients between the index of February SPV multiplied by -1
and April precipitation
variations. In (c) and (d), it is the same as for (a) and (b) but between March ASO and April
200 hPa zonal wind and April precipitation variations. Dots denote
significance at the 95 % confidence level, according to the Student's
t test. The long-term linear trend and seasonal cycle in all variables were
removed before the correlation analysis. The ASO data are from SWOOSH, zonal
wind from NCEP-2 and precipitation from GPCP.
In order to further confirm the possible influence of ASO on precipitation
in the northwestern United States, a transient experiment (1955–2005) based
on the atmosphere–ocean coupled WACCM4 model is added to confirm whether the
ASO can cause the Victoria-mode SST in the North Pacific and
rainfall anomalies in the northwestern United States by itself. Note that the ozone
forcing in the experiment is specified, which is derived from the CMIP5
ensemble mean ozone output. Please refer to R8 in Table 1 for a detailed
description of the experiment. Figure 12 shows the correlation coefficients
between the specified March ASO variations and simulated April zonal wind (U) at 500 hPa,
SST and precipitation anomalies for the period 1955–2005. The significant
and leading effects of the specified ASO anomalies on 500 hPa U, the
Victoria mode in the North Pacific and rainfall anomalies in the
northwestern United States are well captured (Fig. 12). As the ozone forcing
in the experiment is specified, the relationships between ASO and U and SST
and precipitation could only be caused by ASO influencing U and then U
influencing SST and precipitation; the ASO changes are completely
independent of polar vortex. The leading relationship between ASO and
precipitation in the northwestern United States can be found in
observations, time-slice experiments (R1–7) and a transient experiment
with specified ozone (R8). Thus, we have shown that the relationship between
March ASO and April precipitation in the northwestern US in the observations
and the underlying mechanisms can be verified by WACCM4.
Discussion and summary
Many observations and simulations have shown that ASO variations have a
significant impact on Northern Hemisphere tropospheric climate, but few
studies have focused on regional characteristics. Using observations,
reanalysis datasets and WACCM4, we have shown that the March ASO changes
have a significant effect on April precipitation in the northwestern United
States (mainly in Washington and Oregon), with a lead of 1–2 months. When
the March ASO is anomalously high, April precipitation decreases in the
northwestern United States and vice versa for low ASO.
During positive ASO events, the zonal wind changes over the North Pacific
exhibit a tripolar mode with a zonal distribution, i.e., enhanced westerlies
in the high and low latitudes of the North Pacific and weakened westerlies
in the midlatitudes. The anomalous wind can extend eastward to North
America, causing anomalous circulation in western North America. The
climatological wind over the northwestern United States blows from west to
east, bringing moisture from the Pacific to the western United States. Such
circulation anomalies force an anomalous cyclone in the western United
States in the middle and upper troposphere, which reduces the climatological
wind. It would decrease the water vapor concentration in the air over the
northwestern United States. At the same time, downwelling in the
northwestern US is enhanced. The two processes possibly decrease April
precipitation in the northwestern US. When the March ASO decreases, the
effect is just the opposite.
The WACCM4 model is used to confirm the statistical results of observations
and the reanalysis data. The results of the model simulation in which we
only change the ASO forcing do not reflect the observed precipitation
anomalies in the northwestern United States in April, i.e., the pattern of
simulated April precipitation and circulation anomalies in the western North
America shifted a little further to the north than observed. It is found
that SST anomalies over North Pacific caused by ASO changes are likely to
interact with ASO changes to jointly influence precipitation in the
northwestern United States. Thus, the ASO influences precipitation anomalies
over the northwestern United States in two ways. First, the stratospheric
circulation anomalies caused by the ASO change can propagate downward to the
North Pacific troposphere and directly influence precipitation over the
northwestern United States. Second, the ASO changes generate SST anomalies
over the North Pacific that act as a bridge (Xie et al., 2017a), allowing
the ASO changes to affect precipitation in the northwestern United States.
It is well known that the spring ASO variations are related to changes in
the winter Arctic stratospheric vortex (SPV). The strength of the winter SPV
can affect spring ASO, and then the ASO affects tropospheric teleconnection
and precipitation in the northwestern United States (indirect effect of
the SPV). The strength of the winter SPV may also have a direct leading effect
on tropospheric teleconnection (Baldwin and Dunkerton, 2001; Black et al.,
2005, 2006, 2009) and precipitation in the northwestern United States in
spring. A question arises here: can the stratospheric polar vortex
variability in late winter be a better factor for leading spring
precipitation variations in the northwestern United States than the spring
ASO anomalies? Figure 13 shows the correlation coefficients between the
February SPV (multiplied by -1) index and April 200 hPa zonal wind and
precipitation variations (Fig. 13a and b) and between March ASO and April
200 hPa zonal wind and precipitation (Fig. 13c and d). The SPV index is
defined as the strength of the stratospheric polar vortex, following Zhang
et al. (2018). It is found that the relationship between the strength of
February SPV and the variations in 200 hPa zonal wind and precipitation is
significant (Fig. 13a and b), indicating indirect or direct effects of
winter SPV on spring tropospheric climate. However, the relationship is not
stronger than that between March ASO and April 200 hPa zonal wind and
precipitation (Fig. 13c and d). In this study, we try to state that the ASO
changes could influence precipitation in the northwestern United States,
emphasizing the influence of stratospheric ozone on tropospheric regional
climate. As for the effect of coupling between dynamical and radiative
processes in spring on precipitation, this is an interesting question that
deserves further investigation.
The SWOOSH ozone dataset is available at
https://www.esrl.noaa.gov/csd/groups/csd8/swoosh/ (last access:
25 April 2018; Davis et al., 2016). The GOZCARDS ozone dataset is available at
https://disc.gsfc.nasa.gov/datasets/GozSmlpO3_V1/summary?keywords=gozcards
(last access: 18 January 2019; Froidevaux et al., 2015). The precipitation dataset from GPCC
can be obtained via the website https://climatedataguide.ucar.edu/climate-data/gpcc-global-precipitation-climatology-centre
(last access: 18 January 2019; Schneider et al., 2008) and that from GPCP is available at
http://gpcp.umd.edu/ (last access: 18 January 2019; Adler et al., 2003). The
CESM can be downloaded at http://www.cesm.ucar.edu/models/current.html (last access:
18 January 2019; Garcia et al., 2007).
XM and FX designed the study and contributed to
data analysis, interpretation and paper writing. JL and XZ contributed to the
discussion and interpretation of the paper. WT, RD, CS and JZ contributed
to paper writing. All authors reviewed the
paper.
The authors declare that they have no conflict of
interest.
This article is part of the special issue “The Polar Stratosphere in a Changing Climate
(POLSTRACC) (ACP/AMT inter-journal SI)”. It is not associated with a
conference.
Acknowledgements
Funding for this project was provided by the National
Natural Science Foundation of China (41630421, 41790474 and 41575039). We
acknowledge ozone datasets from the SWOOSH and GOZCARDS, precipitation from
GPCC and GPCP, meteorological fields from NCEP-2, SST from the UK Met Office
Hadley Centre, and WACCM4 from NCAR.
Edited by: Bjoern-Martin Sinnhuber
Reviewed by: two anonymous referees
References
Adler, R. F., Huffman, G. J., Chang, A., Ferraro, R., Xie, P. P., Janowiak,
J., Rudolf, B., Schneider, U., Curtis, S., Bolvin, D., Gruber, A., Susskind,
J., Arkin, P., and Nelkin, E.: The version-2 global precipitation climatology
project (GPCP) monthly precipitation analysis (1979–present),
J. Hydrometeorol., 4, 1147–1167, 2003.Archer, C. L. and Caldeira, K.: Historical trends in the jet streams,
Geophys. Res. Lett., 35, L08803, 10.1029/2008GL033614, 2008.Baldwin, M. P. and Dunkerton, T. J.: Stratospheric harbingers of anomalous
weather regimes, Science, 294, 581–584, 10.1126/science.1063315, 2001.Barlow, M., Nigam, S., and Berbery, E. H.: ENSO, Pacific decadal
variability, and US summertime precipitation, drought, and stream flow, J.
Climate, 14, 2105–2128, 10.1175/1520-0442(2001)014<2105:EPDVAU>2.0.CO;2, 2001.Bitz, C. M. and Polvani, L. M.: Antarctic climate response to stratospheric
ozone depletion in a fine resolution ocean climate model, Geophys. Res.
Lett., 39, L20705, 10.1029/2012GL053393, 2012.Black, R. X. and Mcdaniel, B. A.: The Dynamics of Northern Hemisphere
Stratospheric Final Warming Events, J. Atmos. Sci., 64, 2932–2946,
10.1175/Jas3981.1, 2006.Black, R. X. and Mcdaniel, B. A.: SubMonthly polar vortex variability and
stratosphere-troposphere coupling in the Arctic, J. Climate, 22, 5886–5901,
10.1175/2009JCLI2730.1, 2009.Black, R. X., Mcdaniel, B. A., and Robinson, W. A.: Stratosphere Troposphere
Coupling during Spring Onset, J. Climate, 19, 4891–4901,
10.1175/Jcli3907.1, 2005.Cagnazzo, C. and Manzini, E.: Impact of the Stratosphere on the Winter
Tropospheric Teleconnections between ENSO and the North Atlantic and
European Region, J. Climate, 22, 1223–1238, 10.1175/2008JCLI2549.1,
2009.Calvo, N., Polvani, L. M., and Solomon, S.: On the surface impact of Arctic
stratospheric ozone extremes, Environ. Res. Lett., 10, 094003,
10.1088/1748-9326/10/9/094003, 2015.Charlton, A. J. and Polvani, L. M.: A new look at stratospheric sudden
warmings. Part I: Climatology and modeling benchmarks, J. Climate, 20,
449–469, 10.1175/JCLI3996.1, 2007.Cheung, J. C. H., Haigh, J. D., and Jackson, D. R.: Impact of EOS MLS ozone
data on medium-extended range ensemble weather forecasts, J. Geophys. Res.,
119, 9253–9266, 10.1002/2014JD021823, 2014.Davis, S. M., Rosenlof, K. H., Hassler, B., Hurst, D. F., Read, W. G., Vömel,
H., Selkirk, H., Fujiwara, M., and Damadeo, R.: The Stratospheric Water and
Ozone Satellite Homogenized (SWOOSH) database: a long-term database for
climate studies, Earth Syst. Sci. Data, 8, 461–490,
10.5194/essd-8-461-2016, 2016.Feldstein, S. B.: Subtropical Rainfall and the Antarctic Ozone Hole,
Science, 332, 925–926, 10.1126/science.1206834, 2011.Forster, P. M. D. and Shine, K. P.: Radiative forcing and temperature trends
from stratospheric ozone changes, J. Geophys. Res., 102, 10841–10855,
10.1029/96JD03510, 1997.Froidevaux, L., Anderson, J., Wang, H.-J., Fuller, R. A., Schwartz, M. J.,
Santee, M. L., Livesey, N. J., Pumphrey, H. C., Bernath, P. F., Russell III,
J. M., and McCormick, M. P.: Global OZone Chemistry And Related trace gas
Data records for the Stratosphere (GOZCARDS): methodology and sample results
with a focus on HCl, H2O, and O3, Atmos. Chem. Phys., 15, 10471–10507,
10.5194/acp-15-10471-2015, 2015.Gabriel, A., Peters, D., Kirchner, I., and Graf, H. F.: Effect of zonally
asymmetric ozone on stratospheric temperature and planetary wave
propagation, Geophys. Res. Lett., 34, L06807, 10.1029/2006GL028998,
2007.Garcia, R. R., Marsh, D. R., Kinnison, D. E., Boville, B. A., and Sassi, F.:
Simulation of secular trends in the middle atmosphere, 1950–2003, J.
Geophys. Res., 112, D09301, 10.1029/2006JD007485, 2007.Gerber, E. P. and Son, S. W.: Quantifying the Summertime Response of the
Austral Jet Stream and Hadley Cell to Stratospheric Ozone and Greenhouse
Gases, J. Climate, 27, 5538–5559, 10.1175/JCLI-D-13-00539.1, 2014.Gillett, N. P., Scinocca, J. F., Plummer, D. A., and Reader, M. C.:
Sensitivity of climate to dynamically-consistent zonal asymmetries in ozone,
Geophys. Res. Lett., 36, L10809, 10.1029/2009GL037246, 2009.Graf, H. F. and Walter, K.: Polar vortex controls coupling of North Atlantic
Ocean and atmosphere, Geophys. Res. Lett., 32, L01704,
10.1029/2004GL020664, 2005.Haigh, J. D.: The Role of Stratospheric Ozone in Modulating the Solar
Radiative Forcing of Climate, Nature, 370, 544–546, 10.1038/370544a0,
1994.Holland, M. M., Bailey, D. A., Briegleb, B. P., Light, B., and Hunke, E.:
Improved Sea Ice Shortwave Radiation Physics in CCSM4: The Impact of Melt
Ponds and Aerosols on Arctic Sea Ice, J. Climate, 25, 1413–1430,
10.1175/JCLI-D-11-00078.1, 2012.Hu, Y., Tao, L., and Liu, J.: Poleward expansion of the Hadley circulation
in CMIP5 simulations, Adv. Atmos. Sci., 30, 790–795,
10.1007/s00376-012-2187-4, 2013.Huffman, G. J., Adler, R. F., Arkin, P., Chang, A., Ferraro, R., Gruber, A.,
Janowiak, J., McNab, A., Rudolf, B., and Schneider, U.: The Global
Precipitation Climatology Project (GPCP) Combined Precipitation Dataset, B.
Am. Meteorol. Soc., 78, 5–20, 10.1175/1520-0477(1997)078<0005:TGPCPG>2.0.Co;2, 1997.Ineson, S. and Scaife, A. A.: The role of the stratosphere in the European
climate response to El Nino, Nat. Geosci., 2, 32–36, 10.1038/NGEO381,
2009.Ivy, D. J., Solomon, S., Calvo, N., and Thompson, D. W.: Observed
connections of Arctic stratospheric ozone extremes to Northern Hemisphere
surface climate, Environ. Res. Lett., 12, 024004,
10.1088/1748-9326/aa57a4, 2017.Kang, S. M., Polvani, L. M., Fyfe, J. C., and Sigmond, M.: Impact of Polar
Ozone Depletion on Subtropical Precipitation, Science, 332, 951–954,
10.1126/science.1202131, 2011.Karpechko, A. Y., Perlwitz, J., and Manzini, E.: A model study of
tropospheric impacts of the Arctic ozone depletion 2011, J. Geophys. Res.,
119, 7999–8014, 10.1002/2013JD021350, 2014.Kidston, J., Scaife, A. A., Hardiman, S. C., Mitchell, D. M., Butchart, N.,
Baldwin, M. P., and Gray, L. J.: Stratospheric influence on tropospheric jet
streams, storm tracks and surface weather, Nat. Geosci., 8, 433–440,
10.1038/NGEO2424, 2015.
Labitzke, K. and Naujokat, B.: The lower Arctic stratosphere in winter since
1952, Sparc Newsletter, 15, 11–14, 2000.Lau, K. M., Kim, K. M., and Shen, S. S.: Potential predictability of
seasonal precipitation over the U.S. from canonical ensemble correlation
predictions, Geophys. Res. Lett., 29, 1–4, 10.1029/2001GL014263, 2002.Li, F., Vikhliaev, Y. V., Newman, P. A., Pawson, S., Perlwitz, J., Waugh, D.
W., and Douglass, A. R.: Impacts of Interactive Stratospheric Chemistry on
Antarctic and Southern Ocean Climate Change in the Goddard Earth Observing
System, Version 5 (GEOS-5), J. Climate, 29, 3199–3218,
10.1175/JCLI-D-15-0572.1, 2016.Lu, J., Deser, C., and Reichler, T.: Cause of the widening of the tropical
belt since 1958, Geophys. Res. Lett., 36, L03803, 10.1029/2008GL036076,
2009.Manney, G. L., Santee, M. L., Rex, M., Livesey, N. J., Pitts, M. C.,
Veefkind, P., Nash, E. R., Wohltmann, I., Lehmann, R., Froidevaux, L.,
Poole, L. R., Schoeberl, M. R., Haffner, D. P., Davies, J., Dorokhov, V.,
Gernandt, H., Johnson, B., Kivi, R., Kyrö, E., Larsen, N., Levelt, P.
F., Makshtas, A., McElroy, C. T., Nakajima, H., Parrondo, M. C., Tarasick,
D. W., von der Gathen, P., Walker, K. A., and Zinoviev, N. S.: Unprecedented
Arctic ozone loss in 2011, Nature, 478, 469–475,
10.1038/nature10556, 2011.Manney, G. L. and Lawrence, Z. D.: The major stratospheric final warming in
2016: dispersal of vortex air and termination of Arctic chemical ozone loss,
Atmos. Chem. Phys., 16, 15371–15396, 10.5194/acp-16-15371-2016, 2016.Marsh, D. R., Mills, M. J., Kinnison, D. E., Lamarque, J. F., Calvo, N., and
Polvani, L. M.: Climate Change from 1850 to 2005 Simulated in CESM1(WACCM),
J. Climate, 26, 7372–7391, 10.1175/JCLI-D-12-00558.1, 2013.McCormack, J. P., Nathan, T. R., and Cordero, E. C.: The effect of zonally
asymmetric ozone heating on the Northern Hemisphere winter polar
stratosphere, Geophys. Res. Lett., 38, 1–5, 10.1029/2010GL045937,
2011.McLandress, C., Shepherd, T. G., Scinocca, J. F., Plummer, D. A., Sigmond,
M., Jonsson, A. I., and Reader, M. C.: Separating the dynamical effects of
climate change and ozone depletion. Part II: Southern Hemisphere
troposphere, J. Climate, 24, 1850–1868, 10.1175/2010JCLI3958.1, 2011.Min, S. K. and Son, S. W.: Multimodel attribution of the Southern Hemisphere
Hadley cell widening: Major role of ozone depletion, J. Geophys. Res., 118,
3007–3015, 10.1002/jgrd.50232, 2013.Namias, J.: Some causes of U.S. drought, J. Clim. Appl. Meteorol., 22,
30–39, 10.1175/1520-0450(1983)022<0030:Scousd>2.0.Co;2, 1983.Neale, R. B., Richter, J., Park, S., Lauritzen, P. H., Vavrus, S. J., Rasch,
P. J., and Zhang, M. H.: The Mean Climate of the Community Atmosphere Model
(CAM4) in Forced SST and Fully Coupled Experiments, J. Climate, 26,
5150–5168, 10.1175/JCLI-D-12-00236.1, 2013.Nowack, P. J., Abraham, N. L., Maycock, A. C., Braesicke, P., Gregory, J.
M., Joshi, M. M., Osprey, A., and Pyle, J. A.: A large ozone-circulation
feedback and its implications for global warming assessments, Nat. Clim.
Change, 5, 41–45, 10.1038/NCLIMATE2451, 2015.Nowack, P. J., Braesicke, P., Abraham, N. L., and Pyle, J. A.: On the role
of ozone feedback in the ENSO amplitude response under global warming,
Geophys. Res. Lett., 44, 3858–3866, 10.1002/2016GL072418, 2017.Nowack, P. J., Abraham, N. L., Braesicke, P., and Pyle, J. A.: The impact of
stratospheric ozone feedbacks on climate sensitivity estimates, J. Geophys.
Res., 123, 4630–4641, 10.1002/2017JD027943, 2018.Pawson, S. and Naujokat, B.: The cold winters of the middle 1990s in the
northern lower stratosphere, J. Geophys. Res., 104, 14209–14222,
10.1029/1999JD900211, 1999.Polvani, L. M., Waugh, D. W., Correa, G. J., and Son, S.-W.: Stratospheric
ozone depletion: The main driver of twentieth-century atmospheric
circulation changes in the Southern Hemisphere, J. Climate, 24, 795–812,
10.1175/2010JCLI3772.1, 2011.Ramaswamy, V., Schwarzkopf, M. D., and Randel, W. J.: Fingerprint of ozone
depletion in the spatial and temporal pattern of recent lower-stratospheric
cooling, Nature, 382, 616–618, 10.1038/382616a0, 1996.Randel, W. J.: The Seasonal Evolution of Planetary-Waves in the
Southern-Hemisphere Stratosphere and Troposphere, Q. J.
Roy. Meteorol. Soc., 114, 1385–1409, 10.1002/qj.49711448403,
1988.Randel, W. J. and Wu, F.: Cooling of the arctic and antarctic polar
stratospheres due to ozone depletion, J. Climate, 12, 1467–1479,
10.1175/1520-0442(1999)012<1467:COTAAA>2.0.Co;2, 1999.Randel, W. J. and Wu, F.: A stratospheric ozone profile data set for
1979-2005: Variability, trends, and comparisons with column ozone data, J.
Geophys. Res., 112, D06313, 10.1029/2006JD007339, 2007.Ravishankara, A. R., Turnipseed, A. A., Jensen, N. R., Barone, S., Mills,
M., Howard, C. J., and Solomon, S.: Do hydrofluorocarbons destroy
stratospheric ozone?, Science, 263, 71–75, 10.1126/science.263.5143.71,
1994.Ravishankara, A. R., Daniel, J. S., and Portmann, R. W.: Nitrous oxide
(N2O): the dominant ozone-depleting substance emitted in the 21st century,
Science, 326, 123–125, 10.1126/science.1176985, 2009.
Rayner, N. A., Parker, D. E., Horton, E. B., Folland, C. K., Alexander, L.
V., and Rowell, D. P.: Global analyses of sea surface temperature, sea ice,
and night marine air temperature since the late nineteenth century, J.
Geophys. Res., 108, 4407, 2003.Reichler, T., Kim, J., Manzini, E., and Kroger, J.: A stratospheric
connection to Atlantic climate variability, Nat. Geosci., 5, 783–787,
10.1038/NGEO1586, 2012.Russell, J. L., Dixon, K. W., Gnanadesikan, A., Stouffer, R. J., and
Toggweiler, J. R.: The Southern Hemisphere westerlies in a warming world:
Propping open the door to the deep ocean, J. Climate, 19, 6382–6390,
10.1175/JCLI3984.1, 2006.
Schneider, U., Fuchs, T., Meyer-Christoffer, A., and Rudolf, B.: Global
precipitation analysis products of the GPCC, Global Precipitation Climatology
Centre, 12 pp., 2008.Smith, K. L. and Polvani, L. M.: The surface impacts of Arctic stratospheric
ozone anomalies, Environ. Res. Lett., 9, 074015,
10.1088/1748-9326/9/7/074015, 2014.Solomon, S.: Antarctic ozone: Progress towards a quantitative understanding,
Nature, 347, 354, 10.1038/347347a0, 1990.Solomon, S.: Stratospheric ozone depletion: A review of concepts and
history, Rev. Geophys., 37, 275–316, 10.1029/1999RG900008, 1999.Son, S.-W., Tandon, N. F., Polvani, L. M., and Waugh, D. W.: Ozone hole and
Southern Hemisphere climate change, Geophys. Res. Lett., 36, L15705,
10.1029/2009GL038671, 2009.
Son, S.-W., Gerber, E. P., Perlwitz, J., Polvani, L. M., Gillett, N. P.,
Seo, K.-H., Eyring, V., Shepherd, T. G., Waugh, D., Akiyoshi, H., Austin,
J., Baumgaertner, A., Bekki, S., Braesicke, P., Brühl, C., Butchart, N.,
Chipperfield, M. P., Cugnet, D., Dameris, M., Dhomse, S., Frith, S., Garny,
H., Garcia, R., Hardiman, S. C., Jöckel, P., Lamarque, J. F., Mancini,
E., Marchand, M., Michou, M., Nakamura, T., Morgenstern, O., Pitari, G.,
Plummer, D. A., Pyle, J., Rozanov, E., Scinocca, J. F., Shibata, K., Smale,
D., Teyssèdre, H., Tian, W., and Yamashita, Y.: Impact of stratospheric
ozone on Southern Hemisphere circulation change: A multimodel assessment, J.
Geophys. Res., 115, D00M07, doi.org/10.1029/2010JD014271, 2010.Thompson, D. W. J. and Solomon, S.: Interpretation of recent Southern
Hemisphere climate change, Science, 296, 895–899,
10.1126/science.1069270, 2002.Thompson, D. W. J., Solomon, S., Kushner, P. J., England, M. H., Grise, K.
M., and Karoly, D. J.: Signatures of the Antarctic ozone hole in Southern
Hemisphere surface climate change, Nat. Geosci., 4, 741–749,
10.1038/NGEO1296, 2011.Ting, M. and Wang, H.: Summertime US Precipitation Variability and Its
Relation toPacific Sea Surface Temperature, J. Climate, 10, 1853–1873,
10.1175/1520-0442(1997)010<1853:SUSPVA>2.0.CO;2,
1997.Tung, K. K.: On the Relationship between the Thermal Structure of the
Stratosphere and the Seasonal Distribution of Ozone, Geophys. Res. Lett.,
13, 1308–1311, 10.1029/GL013i012p01308, 1986.Wang, F., Yang, S., Higgins, W., Li, Q. P., and Zuo, Z. Y.: Long-term
changes in total and extreme precipitation over China and the U.S. and their
links to oceanic-atmospheric features, Int. J. Climatol., 34, 286–302,
10.1002/joc.3685, 2014.Wang, H. and Ting, M. F.: Covariabilities of winter US precipitation and
Pacific Sea surface temperatures, J. Climate, 13, 3711–3719,
10.1175/1520-0442(2000)013<3711:Cowusp>2.0.Co;2,
2000.
Wang, L., Ting, M., and Kushner, P. J.: A robust empirical seasonal prediction
of winter NAO and surface climate, Sci. Rep., 7, 279, 2017.Waugh, D. W., Garfinkel, C. I., and Polvani, L. M.: Drivers of the Recent
Tropical Expansion in the Southern Hemisphere: Changing SSTs or Ozone
Depletion?, J. Climate, 28, 6581–6586, 10.1175/JCLI-D-15-0138.1, 2015.
WMO: Scientific Assessment of Ozone depletion: 2002. In: Global Ozone
Research and Monitoring Project, Report No. 47, Geneva, 498 pp., 2003.
WMO: Scientific Assessment of Ozone Depletion: 2010. WMO Tech. Note 52,
World Meteorological Organization, Geneva, Switzerland, 516 pp., 2011.Xie, F., Li, J., Tian, W., Fu, Q., Jin, F.-F., Hu, Y., Zhang, J., Wang, W.,
Sun, C., Feng, J., Yang, Y., and Ding, R.: A connection from Arctic
stratospheric ozone to El Niño-Southern Oscillation, Environ. Res.
Lett., 11, 124026, 10.1088/1748-9326/11/12/124026, 2016.Xie, F., Li, J., Zhang, J., Tian, W., Hu, Y., Zhao, S., Sun, C., Ding, R.,
Feng, J., and Yang, Y.: Variations in North Pacific sea surface temperature
caused by Arctic stratospheric ozone anomalies, Environ. Res. Lett., 12,
114023, 10.1088/1748-9326/aa9005, 2017a.
Xie, F., Zhang, J., Sang, W., Li, Y., Qi, Y., Sun, C., and Shu, J.: Delayed
effect of Arctic stratospheric ozone on tropical rainfall, Atmos. Sci.
Lett., 18, 409–416, 2017b.
Xie, F., Ma, X., Li, J., Huang, J., Tian, W., Zhang, J., Hu, Y., Sun, C.,
Zhou, X., Feng, J., and Yang, Y.: An advanced impact of Arctic stratospheric
ozone changes on spring precipitation in China, Clim. Dynam., 51, 4029–4041,
do:10.1007/s00382-018-4402-1, 2018.Yin, J. H.: A consistent poleward shift of the storm tracks in simulations
of 21st century climate, Geophys. Res. Lett., 32, L18701,
10.1029/2005GL023684, 2005.Zhang, J. K., Tian, W. S., Chipperfield, M. P., Xie, F., and Huang, J. L.:
Persistent shift of the Arctic polar vortex towards the Eurasian continent
in recent decades, Nat. Clim. Change., 6, 1094–1099,
10.1038/nclimate3136, 2016.Zhang J. K., Tian, W. S., Xie, F., Chipperfield, M. P., Feng, W. H., Son,
S-W., Abraham, N. L., Archibald, A. T., Bekki, S., Butchart, N., Deushi, M.,
Dhomse, S., Han, Y. Y., Jöckel, P., Kinnison, D., Kirner, O., Michou,
M., Morgenstern, O., O'Connor, F. M., Pitari, G., Plummer, D. A., Revell, L.
E., Rozanov, E., Visioni, D., Wang, W. K., and Zeng, G.: Stratospheric ozone
loss over the Eurasian continent induced by the polar vortex shift, Nat.
Commun., 9, 206, 10.1038/s41467-017-02565-2, 2018.