Boreal winter rainfall anomaly over the tropical indo-pacific and its effect on northern hemisphere atmospheric circulation in CMIP5 models

2014 ◽  
Vol 31 (4) ◽  
pp. 916-925 ◽  
Author(s):  
Hai Wang ◽  
Qinyu Liu
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Rainfall Anomaly ◽  
Cmip5 Models ◽  
Boreal Winter ◽  
Winter Rainfall

Projections of future atmospheric circulation changes using the extratropical linear step response to tropical precipitation

2021 ◽  
Author(s):  
Natasha Senior ◽  
Adrian Matthews ◽  
Manoj Joshi
Keyword(s):  
Atmospheric Circulation ◽  
Linear Response ◽  
Hydrological Cycle ◽  
Linear Response Theory ◽  
Teleconnection Pattern ◽  
Step Response ◽  
Cmip5 Models ◽  
Boreal Winter ◽  
Response Theory ◽  
Circulation Changes

<p>The global hydrological cycle is expected to intensify under a warming climate. Since extratropical Rossby wave trains are triggered by tropical convection, this will impact the atmospheric circulation in the extratropics. Owing to the approximate linearity of the teleconnection pattern, we can use a method based in linear response theory to quantify this extratropical response using a step response function. We have examined the step response functions for a selection of CMIP5 pre-industrial control runs and reanalysis data,  in particular studying the response during the boreal winter. We found there to a large intermodel spread in the response pattern owing to differences in representations of the model basic state. In the current work, we use a 'perfect model' approach to conduct a systematic study of the performance of the linear response method in projecting future winter-time northern hemisphere circulation changes using the present day (1986-2005) model basic states, comparing these to those projected by CMIP5 models under a 3 degree rise in mean global temperature anomaly above pre-industrial. We demonstrate how, given a projected precipitation change pattern, the linear response theory method can compete with the models in providing faithful projections for the extratropical circulation changes.</p>

A new method for studying the extratropical response to tropical precipitation anomalies and its role in improving projections of Northern Hemisphere climate variability

2020 ◽  
Author(s):  
Natasha Senior ◽  
Manoj Joshi ◽  
Adrian Matthews ◽  
Pranab Deb
Keyword(s):  
Climate Variability ◽  
Northern Hemisphere ◽  
Geopotential Height ◽  
Climate Models ◽  
Linear Response Theory ◽  
Teleconnection Pattern ◽  
Cmip5 Models ◽  
Boreal Winter ◽  
Response Functions ◽  
Tropical Precipitation

<p>Intensification of extreme precipitation and weather events are some of the projections under a 2°C average global temperature increase scenario. Rossby wave trains may be triggered by anomalous tropical precipitation through the interaction of the associated upper level divergent wind and the vorticity gradients of the subtropical jet streams. In this way, anomalous tropical precipitation can influence weather patterns in the Northern Hemisphere. Owing to the quasi-linearity of this teleconnection pattern, it may be studied statistically as a series of signal-response functions. Here the anomalous precipitation events are treated as input forcings and the resulting geopotential height anomalies are the output signals. Through calculating the response functions we are able to realistically capture the 250 hPa geopotential height response to a step-like change in precipitation over the Maritime Continent or the eastern Indian Ocean during the boreal winter. When examining these responses using the same forcing for a selection of CMIP5 models, we find that there is a large inter-model spread, owing to differences in the model basic state. Since these teleconnection patterns are not faithfully represented in climate models, this can obscure our ability to develop realistic projections of atmospheric circulation and extreme weather. We discuss the potential of the linear response theory method to provide improved projections for Northern Hemisphere climate variability.</p>

scholarly journals Origins of Biases in CMIP5 Models Simulating Northwest Pacific Summertime Atmospheric Circulation Anomalies during the Decaying Phase of ENSO

2018 ◽  
Vol 31 (14) ◽  
pp. 5707-5729 ◽  
Author(s):  
Weichen Tao ◽  
Gang Huang ◽  
Renguang Wu ◽  
Kaiming Hu ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Southern Oscillation ◽  
Coupled Model ◽  
Tropical Indian Ocean ◽  
Shortwave Radiation ◽  
Cmip5 Models ◽  
Northwest Pacific ◽  
Circulation Anomalies ◽  
Atmospheric Circulation Anomalies ◽  
Sst Anomalies

Abstract The present study documents the biases of summertime northwest Pacific (NWP) atmospheric circulation anomalies during the decaying phase of ENSO and investigates their plausible reasons in 32 models from phase 5 of the Coupled Model Intercomparison Project. Based on an intermodel empirical orthogonal function (EOF) analysis of El Niño–Southern Oscillation (ENSO)-related 850-hPa wind anomalies, the dominant modes of biases are extracted. The first EOF mode, explaining 21.3% of total intermodel variance, is characterized by a cyclone over the NWP, indicating a weaker NWP anticyclone. The cyclone appears to be a Rossby wave response to unrealistic equatorial western Pacific (WP) sea surface temperature (SST) anomalies related to excessive equatorial Pacific cold tongue in the models. On one hand, the cold SST biases increase the mean zonal SST gradient, which further intensifies warm zonal advection, favoring the development and persistence of equatorial WP SST anomalies. On the other hand, they reduce the anomalous convection caused by ENSO-related warming, and the resultant increase in downward shortwave radiation contributes to the SST anomalies there. The second EOF mode, explaining 18.6% of total intermodel variance, features an anticyclone over the NWP with location shifted northward. The related SST anomalies in the Indo-Pacific sector show a tripole structure, with warming in the tropical Indian Ocean and equatorial central and eastern Pacific and cooling in the NWP. The Indo-Pacific SST anomalies are highly controlled by ENSO amplitude, which is determined by the intensity of subtropical cells via the adjustment of meridional and vertical advection in the models.

scholarly journals Changes in the Low Latitude Atmospheric Circulation at the End of the 21stCentury Simulated by CMIP5 Models under Global Warming

Atmosphere ◽  
2013 ◽  
Vol 23 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Yoo-Rim Jung ◽  
Da-Hee Choi ◽  
Hee-Jeong Baek ◽  
Chunho Cho
Keyword(s):  
Global Warming ◽  
Atmospheric Circulation ◽  
Cmip5 Models ◽  
Low Latitude

scholarly journals Interhemispheric asymmetry of climate change projections of boreal winter surface winds in CanESM5 large ensemble simulations

2021 ◽  
Author(s):  
Bin Yu ◽  
Xuebin Zhang ◽  
Guilong Li ◽  
Wei Yu
Keyword(s):  
Climate Variability ◽  
Wind Power ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Boreal Winter ◽  
Interhemispheric Asymmetry ◽  
Large Ensemble ◽  
Internal Climate Variability ◽  
Climate Simulations ◽  
Extreme Wind

Abstract A recent study of future changes in global wind power using an ensemble of ten CMIP5 climate simulations indicated an interhemispheric asymmetry of wind power changes over the 21st century, featured by power decreases across the Northern Hemisphere mid-latitudes and increases across the tropics and subtropics of the Southern Hemisphere. Here we analyze future global projections of surface mean and extreme winds by means of a single-model initial-condition 50-member ensemble of climate simulations generated with CanESM5, the Canadian model participated in CMIP6. We analyze the ensemble mean and spread of boreal winter mean and extreme wind trends over the next half-century (2021-2070) and explore the contribution of internal climate variability to these trends. Surface wind speed is projected to mostly decrease in northern mid-low latitudes and southern mid-latitudes and increase in northern high latitudes and southern tropical and subtropical regions, with considerable regional variations. Large ensemble spreads are apparent, especially with remarkable differences over northern parts of South America and northern Russia. The interhemispheric asymmetry of wind projections is found in most ensemble members, and can be related to large-scale changes in surface temperature and atmospheric circulation. The extreme wind has similar structure of future projections, whereas its reductions tend to be more consistent over northern mid-latitudes. The projected mean and extreme wind changes are attributed to changes in both externally anthropogenic forced and internal climate variability generated components. The spread in wind projections is partially due to large-scale atmospheric circulation variability.

Sign in / Sign up

Export Citation Format

Share Document