Impact of surface warming over Equatorial Pacific ocean in western disturbances precipitation

2020 ◽  
Author(s):  
Asiya Badarunnisa Sainudeen ◽  
Prasanta Sanyal
Keyword(s):  
Pressure Gradient ◽  
Surface Pressure ◽  
Indian Subcontinent ◽  
Sea Surface ◽  
Northeast Monsoon ◽  
Western Disturbances ◽  
Increasing Trend ◽  
Indian Landmass ◽  
Northern Atlantic

<p>Indian subcontinent receives precipitation from the southwest monsoon, northeast monsoon, and western disturbances. Unlike southwest and northeast monsoon, precipitation by western disturbances is less studied in terms of understanding its forcing factors and future behavior. Synoptic weather phenomena that originate in temperate north-Atlantic and the Mediterranean sea are primarily responsible for the moisture convergence towards the Indian landmass through an eastward movement and cause Western Disturbance Precipitation (WDP) in Turkey, Iran, Pakistan, Afghanistan, and northwestern India during winter (December-March). Long term (116 years) WDP shows an increasing trend over most of the regions. To understand the forcing factors in WDP, a long term pressure gradient between the Indian landmass and northern Atlantic has been calculated. This pressure gradient also shows an increasing trend, thereby suggesting its direct influence on WDP. This influence is observed not only in the long term WDP but for each winter month as well. Previous studies showed the impact of Pacific ocean sea surface temperature (SST)  on the modulation of northern Atlantic ocean SST and surface pressure. However, no quantitative estimation on the relation of Pacific SST with WDP is known. Here, an attempt has been made to understand the role of Pacific SST in the long term trend of WDP.</p><p>Changes in SST and convection in the tropical Pacific region determines the interannual variability as well as seasonal climate forecasting all over the world by modulating the air-sea coupling and sea level pressure. Therefore, the potential impact of Pacific SST on WDP has been tested, and a significant correlation between them has been observed. To understand the causal factors behind such relation, statistical analysis like Pearson's correlation analysis was performed by taking the SST of the Nino 3.4 region with the surface pressure of the northern Atlantic and Indian subcontinent. This analysis gave a significant positive correlation (R=0.24) among NINO 3.4 SST and surface pressure over the northern Atlantic and negative correlation (R=-0.28) between NINO 3.4 SST and surface pressure of the Indian region. From this analysis, it is inferred that the Pacific warm pool primarily drives the lower and higher surface pressure over Indian landmass and northern Atlantic, respectively, by modulating the local meridional and zonal circulation, which further dictates WDP.</p><p>References</p><p>Dimri, A. P., et al. "Western disturbances: a review."Reviews of Geophysics 53.2 (2015): 225-246.    </p><p>Enfield, DAVID B., and ALBERTO M. Mestas-Nuñez. "Global modes of ENSO and non-ENSO sea surface temperature variability and their associations with climate."El-Niño and the Southern Oscillation: multiscale variability and global and regional impacts (2000): 89-112.</p><p>    </p>

scholarly journals Climate-change studies in the western Himalaya

2010 ◽  
Vol 51 (54) ◽  
pp. 105-112 ◽  
Author(s):  
M.S. Shekhar ◽  
H. Chand ◽  
S. Kumar ◽  
K. Srinivasan ◽  
A. Ganju
Keyword(s):  
Climate Change ◽  
Indian Subcontinent ◽  
Western Himalaya ◽  
Extreme Weather Events ◽  
The North ◽  
Western Disturbances ◽  
Current Trends ◽  
Weather Events ◽  
Region Data

AbstractThe high Himalayan mountains in the north of India are important sources for generating and maintaining the climate over the entire northern belt of the Indian subcontinent. They also influence extreme weather events, such as the western disturbances over the region during winter. The work presented here describes some current trends in weather and climate over the western Himalaya and suggests some possible explanations in the context of climate change. The work also shows how the special features of Indian orography in the western Himalaya affect climate change in the long term, changing the pattern of precipitation over the region. Data analysis of different ranges of the western Himalaya shows significant variations in temperature and snowfall trends in the past few decades. Possible explanations for the changing climate over the western Himalaya are proposed, in terms of variations in cloudiness. The possible effects of climate change on the number of snowfall days and the occurrences of western disturbances over the western Himalaya are also analysed.

scholarly journals Long-Term Trends of Sea Surface Wind in the Northern South China Sea under the Background of Climate Change

2021 ◽  
Vol 9 (7) ◽  
pp. 752
Author(s):  
Bo Hong ◽  
Jie Zhang
Keyword(s):  
Climate Change ◽  
Northern South China Sea ◽  
Surface Wind ◽  
Sea Surface ◽  
Wind Component ◽  
Sea Surface Wind ◽  
Open Sea ◽  
Increasing Trend ◽  
Long Term Trends

The long-term trends of sea surface wind are of great importance to our understanding of the effects of climate change on the marine environment. In the northern South China Sea (SCS), the long-term changes in coastal sea surface wind are not well-understood. Based on the latest reanalysis (ERA5) data from 1979 to 2019, our analysis showed a decreasing trend in the annual mean wind speed in the coastal area and an increasing trend in the open sea. There was a significant weakening trend in the easterly wind component in the coastal and continental shelf areas, whereas there was an increasing trend in the northerly wind component in the open sea. The Mann–Kendall mutation analysis suggested that there were significant changes in the wind speed and frequency of strong wind. Significant correlations were found between the variation of the wind field and El Niño–Southern Oscillation by wave coherence analysis. The strengthening of the wind stress curl was an important factor for the enhancement of coastal upwelling along the coast of the northern SCS. The wind field plays an important role in modulating the climatic change of significant wave height.

SATELLITE DATA FOR INVESTIGATION OF RECENT STATE AND PROCESSES IN THE SIVASH BAY

2017 ◽  
Author(s):  
Ekaterina Shchurova ◽  
Ekaterina Shchurova ◽  
Rimma Stanichnaya ◽  
Rimma Stanichnaya ◽  
Sergey Stanichny ◽  
...  
Keyword(s):  
Satellite Data ◽  
Water Exchange ◽  
High Salinity ◽  
Meteorological Data ◽  
Sea Surface ◽  
Azov Sea ◽  
Seasonal Wind ◽  
Ice Regime ◽  
Very High

Sivash bay is the shallow-water lagoon of the Azov Sea. Restricted water exchange and high evaporation form Sivash as the basin with very high salinity. This factor leads to different from the Azov Sea thermal and ice regimes of Sivash. Maine aim of the study presented to investigate recent state and changes of the characteristics and processes in the basin using satellite data. Landsat scanners TM, ETM+, OLI, TIRS together with MODIS and AVHRR were used. Additionally NOMADS NOAA and MERRA meteorological data were analyzed. The next topics are discussed in the work: 1. Changes of the sea surface temperature, ice regime and relation with salinity. 2. Coastal line transformation – long term and seasonal, wind impact. 3. Manifestation of the Azov waters intrusions through the Arabat spit, preferable wind conditions.

scholarly journals Interannual variability of larval fish assemblages associated with water masses in winter in the Taiwan Strait during 2007–2013

2021 ◽  
Author(s):  
Yu-Kai Chen ◽  
Chia-Yi Pan ◽  
Yi-Chen Wang ◽  
Hsiu-Ju Tseng ◽  
Bo-Kun Su ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
Taiwan Strait ◽  
Assemblage Structure ◽  
Sea Surface ◽  
Coastal Current ◽  
Annual Variations ◽  
Frontal Zones ◽  
The Taiwan Strait

AbstractIn this study, the interannual variations of ichthyoplankton assemblages in the Taiwan Strait (TS) during the winters of 2007–2013 were determined. The cold China Coastal Current (CCC) and Mixed China Coastal Water (MCCW) intruded into the TS and impinged with the warm Kuroshio Branch Current (KBC) with annual variations. Consequently, the ichthyoplankton community in the TS was mainly structured into two assemblages characterized by differing environmental conditions. The composition of the warm KBC assemblage was relatively stable and was characterized by Diaphus B and Bregmaceros spp. By contrast, the cold MCCW assemblage demonstrated considerable variations over the years, with demersal Gobiidae and Scorpaenidae families considered the most representative. In addition, Benthosema pterotum and Trichiurus spp. were common in both KBC and MCCW assemblages. The distribution of the KBC assemblage demonstrated sharp boundaries in the frontal zones, whereas changes in the assemblage structure between the frontal zones were gradual for the MCCW assemblage, particularly when demersal taxa were dominant. Sea surface temperature and salinity were most strongly associated with variability in the assemblage structure during the study period. Thus, this paper provides a better understanding of long-term larval fish dynamics during winter in the TS.

RETROSPECTIVE ASSESSMENT OF UNREGULATED LATERAL INFLOWS OF THE KUIBYSHEVSKY (NOW ZHIGULYOVSKAYA HYDROPOWER PLANT) HYDRAULIC UNIT OF THE VOLGA RIVER BASIN

2021 ◽  
pp. 87-99
Author(s):  
G. KH. ISMAIYLOV ◽  
◽  
N. V. MURASCHENKOVA ◽  
I. G. ISMAIYLOVA
Keyword(s):  
River Basin ◽  
Air Temperature ◽  
Atmospheric Precipitation ◽  
Total Precipitation ◽  
Volga River ◽  
Hydraulic Unit ◽  
Seasonal Characteristics ◽  
Lateral Inflow ◽  
Increasing Trend

The results of the analysis and assessment of changes in annual and seasonal characteristics of hydrometeorological processes in a private catchment area of the Kuibyshev hydroelectric complex of the Volga river are presented. To analyze the temporal dynamics of the variability of the annual and seasonal characteristics of the hydrometeorological processes in the considered territory of the river basin we used more than 100 years of observations of annual and seasonal fluctuations of lateral inflow, total atmospheric precipitation and air temperature regimes on the Volgariver. Relationship equations for annual and seasonal changes in hydrometeorological characteristics in time are obtained. It was found that long-term fluctuations of hydrometeorological processes (lateral inflow, total atmospheric precipitation and air temperature) are characterized by tendencies (trends). The analysis of these trends showed that the non-standard climatic situation, starting from the 70s of the last century, had a very significant impact on the distribution of annual and especially on the seasonal (low-water and winter) characteristics of hydrometeorological processes. It has been established that non-standard unidirectional changes are found in the fluctuations in the total atmospheric precipitation. If the winter total precipitation is characterized over the 100-year period in question by a continuously decreasing trend,the summer-autumn period is an increasing trend. This leads to the fact that long-term fluctuations in total precipitation during the period of low water are formed as a stationary process. At the same time, the total precipitation of the spring flood and inflowing to the Kuibyshev hydroelectric unit is characterized by a constantly increasing trend.

scholarly journals Long term trends in the sea surface temperature of the Black Sea

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 491-501 ◽  
Author(s):  
G. I. Shapiro ◽  
D. L. Aleynik ◽  
L. D. Mee
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Black Sea ◽  
Sea Surface ◽  
The Black Sea ◽  
The North ◽  
Sst Variability ◽  
Long Term Trends ◽  
Cooling Trend

Abstract. There is growing understanding that recent deterioration of the Black Sea ecosystem was partly due to changes in the marine physical environment. This study uses high resolution 0.25° climatology to analyze sea surface temperature variability over the 20th century in two contrasting regions of the sea. Results show that the deep Black Sea was cooling during the first three quarters of the century and was warming in the last 15–20 years; on aggregate there was a statistically significant cooling trend. The SST variability over the Western shelf was more volatile and it does not show statistically significant trends. The cooling of the deep Black Sea is at variance with the general trend in the North Atlantic and may be related to the decrease of westerly winds over the Black Sea, and a greater influence of the Siberian anticyclone. The timing of the changeover from cooling to warming coincides with the regime shift in the Black Sea ecosystem.

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