A climate classification: Mediterranean, monsoon and westerlies climates

2020 ◽  
Author(s):  
Xin-Gang Dai ◽  
Ping Wang
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
Moisture Transport ◽  
Seasonal Cycle ◽  
Large Scale ◽  
Mediterranean Climate ◽  
Climate Classification ◽  
Dry Land ◽  
Temperature And Precipitation ◽  
Wet Climate

<p>This study aims to develop a large-scale climate classification for investigating the mechanisms of global climate formation in the surface. There are three types of large-scale climates, i.e., monsoon, Mediterranean and westerlies, corresponding respectively to collocation of temperature and precipitation at in-phase, anti-phase and out of phase, during seasonal cycle. The first one is called proper collocation, and the latter two are named as improper collocation, hereafter. The collocations are coupled with different seasonal moisture transport pattern with moisture divergence. Northward/southward moisture transport accompanies a moisture convergence/divergence with more/less precipitation in the season leading to different climate type. As an example, the climate around Tibetan Plateau can be attributed to four regimes, i.e., East Asia monsoon, South Asia monsoon, Central Asia and westerlies regimes, despite of the Köppen climate classification. The Central Asia regime refers to the dry climate in middle and southern part of the area, while the dry land belt with the westerlies regime extends from northern Central Asia throughout the northwestern China. The proper collocation between temperature and precipitation leads to a warm-wet climate over monsoon zones in warm season (May-October), whereas the improper one leads a hot-dry climate in Mediterranean climate areas and the dry land with the westerlies climate regime. By contrast, a mild-wet climate is in Mediterranean or quasi-Mediterranean climate areas in comparison with cold-dry climate in Asian monsoon zone during cold season (November to April). The improper collocation results in land degradation or even desertification in Mediterranean climate areas and the dry land with the westerlies regime with insufficient precipitation and over-evenly distribution of the precipitation during seasonal cycle. The improper collocation is actually made by improper dynamical and thermal dynamical collocation in regional moisture circulation associated with seasonal change of mid-latitude stationary waves in wave number and phase, which is virtually forced by large mountains and land-sea thermal contrast in the surface. Besides, analysis manifests that there exists mutually engagement between the seasonal changes in some properties of the mean moisture flows over monsoon and non-monsoon areas across Tibetan Plateau in Eurasian continent. It implies a dynamical coupling existed in large-scale moisture patterns over the earth surface.</p><p>Keywords: Large-scale climate classification, monsoon, westerlies, Mediterranean climate, Tibetan Plateau</p>

Variability and Predictability of Central Asia River Flows: Antecedent Winter Precipitation and Large-Scale Teleconnections

2008 ◽  
Vol 9 (6) ◽  
pp. 1334-1349 ◽  
Author(s):  
Mathew A. Barlow ◽  
Michael K. Tippett
Keyword(s):  
Climate Variability ◽  
Central Asia ◽  
Moisture Transport ◽  
Large Scale ◽  
River Flow ◽  
Regional Scale ◽  
Warm Season ◽  
Cold Season ◽  
River Flows ◽  
Syr Darya

Abstract Warm season river flows in central Asia, which play an important role in local water resources and agriculture, are shown to be closely related to the regional-scale climate variability of the preceding cold season. The peak river flows occur in the warm season (April–August) and are highly correlated with the regional patterns of precipitation, moisture transport, and jet-level winds of the preceding cold season (November–March), demonstrating the importance of regional-scale variability in determining the snowpack that eventually drives the rivers. This regional variability is, in turn, strongly linked to large-scale climate variability and tropical sea surface temperatures (SSTs), with the circulation anomalies influencing precipitation through changes in moisture transport. The leading pattern of regional climate variability, as resolved in the operationally updated NCEP–NCAR reanalysis, can be used to make a skillful seasonal forecast for individual river flow stations. This ability to make predictions based on regional-scale climate data is of particular use in this data-sparse area of the world. The river flow is considered in terms of 24 stations in Uzbekistan and Tajikistan available for 1950–85, with two additional stations available for 1958–2003. These stations encompass the headwaters of the Amu Darya and Syr Darya, two of the main rivers of central Asia and the primary feeders of the catastrophically shrinking Aral Sea. Canonical correlation analysis (CCA) is used to forecast April–August flows based on the period 1950–85; cross-validated correlations exceed 0.5 for 10 of the stations, with a maximum of 0.71. Skill remains high even after 1985 for two stations withheld from the CCA: the correlation for 1986–2002 for the Syr Darya at Chinaz is 0.71, and the correlation for the Amu Darya at Kerki is 0.77. The forecast is also correlated to the normalized difference vegetation index (NDVI); maximum values exceed 0.8 at 8-km resolution, confirming the strong connection between hydrology and growing season vegetation in the region and further validating the forecast methodology.

scholarly journals Stable isotope compositions of precipitation over Central Asia

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11312
Author(s):  
Junqiang Yao ◽  
Xinchun Liu ◽  
Wenfeng Hu
Keyword(s):  
Central Asia ◽  
Atmospheric Circulation ◽  
Moisture Transport ◽  
Environmental Variables ◽  
Large Scale ◽  
Meteoric Water ◽  
Water Cycle ◽  
East Asian Monsoon ◽  
The Relationship ◽  
Large Scale Atmospheric Circulation

Central Asia is one of the driest regions in the world with a unique water cycle and a complex moisture transport process. However, there is little information on the precipitation δ18O content in Central Asia. We compiled a precipitation δ18O database from 47 meteorological stations across Central Asia to reveal its spatial-temporal characteristics. We determined the relationship between precipitation δ18O and environmental variables and investigated the relationship between δ18O and large-scale atmospheric circulation. The Central Asia meteoric water line was established as δ2H = 7.30 δ18O + 3.12 (R2 = 0.95, n = 727, p < 0.01), and precipitation δ18O ranged from +2‰ to −25.4‰ with a mean of −8.7‰. The precipitation δ18O over Central Asia was related to environmental variables. The δ18O had a significant positive correlation with temperature, and the δ18O-temperature gradient ranged from 0.28‰/°C to 0.68‰/°C. However, the dependence of δ18O on precipitation was unclear; a significant precipitation effect was only observed at the Zhangye and Teheran stations, showing δ18O-precipitation gradients of 0.20‰/mm and −0.08‰/mm, respectively. Latitude and altitude were always significantly correlated with annual δ18O, when considering geographical controls on δ18O, with δ18O/LAT and δ18O/ALT gradients of −0.42‰/° and −0.001‰/m, respectively. But both latitude and longitude were significantly correlated with δ18O in winter. The relationship between δ18O and large-scale atmospheric circulation suggested that the moisture in Central Asia is mainly transported by westerly circulation and is indirectly affected by the Indian monsoon. Meanwhile, the East Asian monsoon may affect the precipitation δ18O content in westerly and monsoon transition regions. These results improve our understanding of the precipitation δ18O and moisture transport in Central Asia, as well as the paleoclimatology and hydrology processes in Central Asia.

Seasonal transition features of large-scale moisture transport in the Asian-Australian monsoon region

2007 ◽  
Vol 24 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Jinhai He ◽  
Chenghu Sun ◽  
Yunyun Liu ◽  
Jun Matsumoto ◽  
Weijing Li
Keyword(s):  
Moisture Transport ◽  
Large Scale ◽  
Monsoon Region ◽  
Seasonal Transition ◽  
Australian Monsoon

Dynamic and Thermodynamic Relations of Distinctive Stratus Clouds on the Lee Side of the Tibetan Plateau in the Cold Season

2013 ◽  
Vol 26 (21) ◽  
pp. 8378-8391 ◽  
Author(s):  
Yi Zhang ◽  
Rucong Yu ◽  
Jian Li ◽  
Weihua Yuan ◽  
Minghua Zhang
Keyword(s):  
Tibetan Plateau ◽  
Large Scale ◽  
Eastern China ◽  
Cold Season ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Primary Role ◽  
Moist Air ◽  
Low Level ◽  
Stratus Clouds

Abstract Given the large discrepancies that exist in climate models for shortwave cloud forcing over eastern China (EC), the dynamic (vertical motion and horizontal circulation) and thermodynamic (stability) relations of stratus clouds and the associated cloud radiative forcing in the cold season are examined. Unlike the stratus clouds over the southeastern Pacific Ocean (as a representative of marine boundary stratus), where thermodynamic forcing plays a primary role, the stratus clouds over EC are affected by both dynamic and thermodynamic factors. The Tibetan Plateau (TP)-forced low-level large-scale lifting and high stability over EC favor the accumulation of abundant saturated moist air, which contributes to the formation of stratus clouds. The TP slows down the westerly overflow through a frictional effect, resulting in midlevel divergence, and forces the low-level surrounding flows, resulting in convergence. Both midlevel divergence and low-level convergence sustain a rising motion and vertical water vapor transport over EC. The surface cold air is advected from the Siberian high by the surrounding northerly flow, causing low-level cooling. The cooling effect is enhanced by the blocking of the YunGui Plateau. The southwesterly wind carrying warm, moist air from the east Bay of Bengal is uplifted by the HengDuan Mountains via topographical forcing; the midtropospheric westerly flow further advects the warm air downstream of the TP, moistening and warming the middle troposphere on the lee side of the TP. The low-level cooling and midlevel warming together increase the stability. The favorable dynamic and thermodynamic large-scale environment allows for the formation of stratus clouds over EC during the cold season.

scholarly journals Indian Monsoon Low-Pressure Systems Feed Up-and-Over Moisture Transport to the Southwestern Tibetan Plateau

2017 ◽  
Vol 122 (22) ◽  
pp. 12,140-12,151 ◽  
Author(s):  
Wenhao Dong ◽  
Yanluan Lin ◽  
Jonathon S. Wright ◽  
Yuanyu Xie ◽  
Fanghua Xu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Moisture Transport ◽  
Indian Monsoon ◽  
Low Pressure ◽  
Low Pressure Systems

scholarly journals Changes in Temperature and Precipitation Extremes in Superparameterized CAM in Response to Warmer SSTs

2017 ◽  
Vol 30 (24) ◽  
pp. 9827-9845 ◽  
Author(s):  
Xin Zhou ◽  
Marat F. Khairoutdinov
Keyword(s):  
Large Scale ◽  
Rain Rate ◽  
Precipitable Water ◽  
Heavy Precipitation ◽  
Global Scale ◽  
Precipitation Extremes ◽  
Temperature And Precipitation ◽  
Hourly Data ◽  
Cloud Resolving Model ◽  
Cold Extremes

Subdaily temperature and precipitation extremes in response to warmer SSTs are investigated on a global scale using the superparameterized (SP) Community Atmosphere Model (CAM), in which a cloud-resolving model is embedded in each CAM grid column to simulate convection explicitly. Two 10-yr simulations have been performed using present climatological sea surface temperature (SST) and perturbed SST climatology derived from the representative concentration pathway 8.5 (RCP8.5) scenario. Compared with the conventional CAM, SP-CAM simulates colder temperatures and more realistic intensity distribution of precipitation, especially for heavy precipitation. The temperature and precipitation extremes have been defined by the 99th percentile of the 3-hourly data. For temperature, the changes in the warm and cold extremes are generally consistent between CAM and SP-CAM, with larger changes in warm extremes at low latitudes and larger changes in cold extremes at mid-to-high latitudes. For precipitation, CAM predicts a uniform increase of frequency of precipitation extremes regardless of the rain rate, while SP-CAM predicts a monotonic increase of frequency with increasing rain rate and larger change of intensity for heavier precipitation. The changes in 3-hourly and daily temperature extremes are found to be similar; however, the 3-hourly precipitation extremes have a significantly larger change than daily extremes. The Clausius–Clapeyron scaling is found to be a relatively good predictor of zonally averaged changes in precipitation extremes over midlatitudes but not as good over the tropics and subtropics. The changes in precipitable water and large-scale vertical velocity are equally important to explain the changes in precipitation extremes.

Sign in / Sign up

Export Citation Format

Share Document