Regional Climates in the GISS General Circulation Model: Surface Air Temperature

1994 ◽  
Vol 7 (2) ◽  
pp. 283-303 ◽  
Author(s):  
Bruce Hewitson
Keyword(s):  
General Circulation Model ◽  
Air Temperature ◽  
General Circulation ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Model Surface ◽  
Regional Climates

scholarly journals Panama’s Current Climate Replicability in a Non-Hydrostatic Regional Climate Model Nested in an Atmospheric General Circulation Model

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1543
Author(s):  
Reinhardt Pinzón ◽  
Noriko N. Ishizaki ◽  
Hidetaka Sasaki ◽  
Tosiyuki Nakaegawa
Keyword(s):  
Regional Climate Model ◽  
Air Temperature ◽  
General Circulation ◽  
Climate Model ◽  
Regional Climate ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Horizontal Resolution ◽  
Temperature And Precipitation ◽  
Current Climate

To simulate the current climate, a 20-year integration of a non-hydrostatic regional climate model (NHRCM) with grid spacing of 5 and 2 km (NHRCM05 and NHRCM02, respectively) was nested within the AGCM. The three models did a similarly good job of simulating surface air temperature, and the spatial horizontal resolution did not affect these statistics. NHRCM02 did a good job of reproducing seasonal variations in surface air temperature. NHRCM05 overestimated annual mean precipitation in the western part of Panama and eastern part of the Pacific Ocean. NHRCM05 is responsible for this overestimation because it is not seen in MRI-AGCM. NHRCM02 simulated annual mean precipitation better than NHRCM05, probably due to a convection-permitting model without a convection scheme, such as the Kain and Fritsch scheme. Therefore, the finer horizontal resolution of NHRCM02 did a better job of replicating the current climatological mean geographical distributions and seasonal changes of surface air temperature and precipitation.

scholarly journals Quantifying the contribution of anthropogenic influence to the East Asian winter monsoon in 1960–2012

2019 ◽  
Vol 19 (15) ◽  
pp. 9903-9911
Author(s):  
Xin Hao ◽  
Shengping He ◽  
Huijun Wang ◽  
Tingting Han
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Winter Monsoon ◽  
Anthropogenic Influence ◽  
Anthropogenic Forcing ◽  
Asian Winter Monsoon

Abstract. The East Asian winter monsoon (EAWM) is greatly influenced by many factors that can be classified as anthropogenic forcing and natural forcing. Here we explore the contribution of anthropogenic influence to the change in the EAWM over the past decades. Under all forcings observed during 1960–2013 (All-Hist run), the atmospheric general circulation model is able to reproduce the climatology and variability of the EAWM-related surface air temperature and 500 hPa geopotential height and shows a statistically significant decreasing EAWM intensity with a trend coefficient of ∼-0.04 yr−1, which is close to the observed trend. By contrast, the simulation, which is driven by the same forcing as the All-Hist run but with the anthropogenic contribution to them removed, shows no decreasing trend in the EAWM intensity. By comparing the simulations under two different forcing scenarios, we further reveal that the responses of the EAWM to the anthropogenic forcing include a rise of 0.6∘ in surface air temperature over East Asia as well as weakening of the East Asian trough, which may result from the poleward expansion and intensification of the East Asian jet forced by the change in temperature gradient in the troposphere. Additionally, compared with the simulation without anthropogenic forcing, the frequency of strong (weak) EAWM occurrence is reduced (increased) by 45 % (from 0 to 10/7). These results indicate that the weakening of the EAWM during 1960–2013 may be mainly attributed to the anthropogenic influence.

Improving predictions of surface air temperature anomalies over Japan by Selective Ensemble Mean technique

2020 ◽  
Author(s):  
J. V. Ratnam ◽  
Takeshi Doi ◽  
Yushi Morioka ◽  
Pascal Oettli ◽  
Masami Nonaka ◽  
...  
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
Surface Air Temperature ◽  
Correlation Coefficients ◽  
Circulation Model ◽  
Skill Score ◽  
Temperature Anomalies ◽  
Selective Ensemble ◽  
Ensemble Mean ◽  
Air Temperature Anomalies

AbstractSelective ensemble mean (SEM) technique is applied to the late spring and summer months (May to August) surface air temperature anomaly predictions of the Scale Interaction Experiment-Frontier Research Center for Global Change Version 2 (SINTEX-F2) coupled general circulation model over Japan. Using the Köppen-Geiger climatic classification we chose four regions over Japan for applying the SEM technique. The SINTEX-F2 ensemble members for the SEM are chosen based on the anomaly correlation coefficients (ACC) of the SINTEX-F2 predicted and observed surface air temperature anomalies. The SEM technique is applied to generate the forecasts of the surface air temperature anomalies for the period 1983 to 2018 using the selected members. Analysis shows the ACC skill score of the SEM prediction to be higher compared to the ACC skill score of predictions obtained by averaging all the 24 members of the SINTEX-F2 (ENSMEAN). The SEM predicted surface air temperature anomalies also have higher hit rate and lower false alarm rate compared to the ENSMEAN predicted anomalies over a range of temperature anomalies. The results indicate the SEM technique to be a simple and easy to apply method to improve the SINTEX-F2 predictions of surface air temperature anomalies over Japan. The better performance of the SEM in generating the surface air temperature anomalies can be partly attributed to realistic prediction of 850hPa geopotential height anomalies over Japan.

Atlantic Atmosphere–Ocean Interaction: A Stochastic Climate Model–Based Diagnosis

2005 ◽  
Vol 18 (7) ◽  
pp. 1086-1095 ◽  
Author(s):  
Timothy J. Mosedale ◽  
David B. Stephenson ◽  
Matthew Collins
Keyword(s):  
Simple Model ◽  
General Circulation Model ◽  
General Circulation ◽  
Climate Model ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Daily Data ◽  
Stochastic Climate Model ◽  
Fully Coupled ◽  
Northeastern Atlantic

Abstract A simple linear stochastic climate model of extratropical wintertime ocean–atmosphere coupling is used to diagnose the daily interactions between the ocean and the atmosphere in a fully coupled general circulation model. Monte Carlo simulations with the simple model show that the influence of the ocean on the atmosphere can be difficult to estimate, being biased low even with multiple decades of daily data. Despite this, fitting the simple model to the surface air temperature and sea surface temperature data from the complex general circulation model reveals an ocean-to-atmosphere influence in the northeastern Atlantic. Furthermore, the simple model is used to demonstrate that the ocean in this region greatly enhances the autocorrelation in overlying lower-tropospheric temperatures at lags from a few days to many months.

scholarly journals Increased Frequency of Summer Extreme Heat Waves over Texas Area Tied to the Amplification of Pacific Zonal SST Gradient

2018 ◽  
Vol 31 (14) ◽  
pp. 5629-5647 ◽  
Author(s):  
Kaiqiang Deng ◽  
Mingfang Ting ◽  
Song Yang ◽  
Yaheng Tan
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
Heat Waves ◽  
Linear Trend ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Summer Precipitation ◽  
Extreme Heat ◽  
Vapor Flux ◽  
Sst Gradient

Abstract Summer extreme heat waves (EHWs) over the Texas area and their trend are investigated using observations and atmospheric general circulation model (AGCM) output. There is a positive linear trend in Texas EHW days for the period 1979–2015. While the interannual variability of the Texas EHWs is linked to ENSO conditions, the upward trend in Texas EHWs is found to be significantly associated with the tropical Pacific zonal SST gradient (PZSSTG). The amplification of PZSSTG leads to both enhanced convection in the western Pacific and suppressed convection in the central-eastern Pacific (i.e., La Niña–like pattern), both of which can induce anomalous anticyclones over the Texas area through two distinct planetary wave trains in the antecedent spring. As a result, anomalously sinking motions and divergent water vapor flux appear over the Texas area, which reduce precipitation and increase downward solar radiation, leading to dry and hot soil that favors the occurrence of Texas summer EHWs. In addition, all AGCMs using observed SSTs as boundary conditions were able to simulate the observed decreasing trend in Texas summer precipitation and the observed increasing trend in Texas summer surface air temperature. The observed relationships between winter PZSSTG and the following spring–summer Texas precipitation/temperature were also reproduced by these models, where the intensified PZSSTG tended to reduce the Texas precipitation while increasing the surface air temperature.

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