scholarly journals Moisture Transport Associated with Southwest Monsoon Rainfall Over Sri Lanka in Relatively Wet and Dry Rainfall Years

2021 ◽  
Author(s):  
Sherly Shelton
Keyword(s):  
Sri Lanka ◽  
Moisture Transport ◽  
Arabian Sea ◽  
Rainfall Variability ◽  
Strong Relationship ◽  
Moisture Flux ◽  
Southwest Monsoon ◽  
Flux Divergence ◽  
Average Rainfall ◽  
Southwest Monsoon Rainfall

Abstract Atmospheric moisture transportation associated with the occurrence of relatively wet and dry southwest monsoon (SWM) years over Sri Lanka is still not fully understood. This study focused on investigating the role of moisture transport in contrast SWM years. We selected seven wet (SWMWet) and nine dry (SWMDry) years for 1985-2015 and found that the whole country experiences above-average (below average) rainfall in SWMWet (SWMDry) years. In SWMWet years, strengthening moisture-laden low-level jets (LLJ) from the Arabian Sea bring a large amount of moisture towards Sri Lanka. In contrast, the weakening of the LLJ from the Arabian Sea direction is observed in SWMDry years. As a consequence, the climatological mean of net moisture flux (4.35 ×105 kg s-1) over the study domain is increased (5.33×105 kg s-1) and decreased (3.98 ×105 kg s-1) in SWMWet and SWMDry years, respectively. With respect to long-term Vertically Integrate Moisture Flux Divergence (VIMFD, –3.28×10-5 kg m-2 s-1), negative anomalous VIMFD (–1.78×10-5 kg m-2 s-1) in SWMWet years and positive anomalous VIMFD (1.44×10-5 kg m-2 s-1) in SWMDry years are recorded, which ascribed above-average and below-average rainfall over the country. Furthermore, strong moisture convergence (divergence) center in the western/ southwestern part of Sri Lanka during the SWMWet (SWMDry) years explain why strong positive and negative SWM rainfall anomalies are concentrated in these two regions. Furthermore, results highlighted a strong relationship between net moisture flux availability and SWM rainfall (r= 0.63) that may explain the observed SWM rainfall variability over the country.

scholarly journals Temporal Rainfall Variabilityand Its Correlation with Temperature over Ranchi, Jharkhand

2019 ◽  
Vol 9 (2) ◽  
pp. 1099-1104
Keyword(s):  
Temporal Variability ◽  
Rainfall Variability ◽  
Research Work ◽  
Winter Season ◽  
Southwest Monsoon ◽  
Annual Rainfall ◽  
Trend Test ◽  
Annual Data ◽  
Positive Trend ◽  
Southwest Monsoon Rainfall

The extent to which rainfall amount varies across an area (spatial) or through time (temporal) is an important characteristic to determine the climate of an area. The discipline that covers this area in Meteorology/Climatology is known as “Rainfall variability”. It is of two types: Areal (Spatial) and Temporal. The temporal variability of rainfall means variation of rainfall as time varies but the area of the location remains the same. The temporal variability of rainfall of a place helps in knowing the rainfall variability with time. Rainfall variability plays an important role in understanding climate change. In this fast growing world, urbanization and industrialization has led to the problem of global warming. As a result of this, there has been a drift rise in temperature. The present research work was taken over to analyze the temporal trend of Rainfall over Ranchi during 1975-2017 and to study its correlation with temperature over Ranchi, Jharkhand during 1975-2009. To analyze the trend in rainfall over Ranchi, rainfall data from 1975-2017 was studied. The annual rainfall ranged from a minimum of 734.6 mm to a highest of 1771.335 mm. The mean, median, coefficient of variance and standard deviation was also found on the monthly, seasonal and annual basis. Through time series graphs of rainfall, a positive trend is detected in summer season while annual, winter and southwest monsoon rainfall appeared as a negative trend. On the other hand, by utilizing non-parametric tests such as Mann-Kendall trend test and Sen Slope, it was found that there was no significant trend at 95% confidence limit in any case. Through the study, it was found that there is a significant correlation of rainfall with temperature over the years 1975-2009. Although it was found to be negative in Summer, Monsoon and Annual data, whereas there was a positive correlation between rainfall and temperature during the winter season.

scholarly journals The phytoplankton bloom in the northwestern Arabian Sea during the southwest monsoon of 1979

1991 ◽  
Vol 96 (C11) ◽  
pp. 20623 ◽  
Author(s):  
John C. Brock ◽  
Charles R. McClain ◽  
Mark E. Luther ◽  
William W. Hay
Keyword(s):  
Arabian Sea ◽  
Phytoplankton Bloom ◽  
Southwest Monsoon

scholarly journals Sensitivity Study of WRF Numerical Modeling for Forecasting Heavy Rainfall in Sri Lanka

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 378 ◽  
Author(s):  
Channa Rodrigo ◽  
Sangil Kim ◽  
Il Jung
Keyword(s):  
Sri Lanka ◽  
Heavy Rainfall ◽  
Weather Prediction ◽  
Wrf Model ◽  
Heavy Rain ◽  
Heavy Precipitation ◽  
Sensitivity Study ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Pressure System

This study aimed to determine the predictability of the Weather Research and Forecasting (WRF) model with different model physics options to identify the best set of physics parameters for predicting heavy rainfall events during the southwest and northeast monsoon seasons. Two case studies were used for the evaluation: heavy precipitation during the southwest monsoon associated with the simultaneous onset of the monsoon, and a low pressure system over the southwest Bay of Bengal that produced heavy rain over most of the country, with heavy precipitation associated with the northeast monsoon associated with monsoon flow and easterly disturbances. The modeling results showed large variation in the rainfall estimated by the model using the various model physics schemes, but several corresponding rainfall simulations were produced with spatial distribution aligned with rainfall station data, although the amount was not estimated accurately. Moreover, the WRF model was able to capture the rainfall patterns of these events in Sri Lanka, suggesting that the model has potential for operational use in numerical weather prediction in Sri Lanka.

scholarly journals The Atmospheric Water Balance over the Semiarid Murray–Darling River Basin

2008 ◽  
Vol 9 (3) ◽  
pp. 521-534 ◽  
Author(s):  
Clara Draper ◽  
Graham Mills
Keyword(s):  
Surface Water ◽  
Water Balance ◽  
River Basin ◽  
Moisture Flux ◽  
Limited Area ◽  
Consecutive Series ◽  
Atmospheric Water ◽  
Flux Divergence ◽  
Murray Darling Basin ◽  
Moisture Flux Divergence

Abstract The atmospheric water balance over the semiarid Murray–Darling River basin in southeast Australia is analyzed based on a consecutive series of 3- to 24-h NWP forecasts from the Australian Bureau of Meteorology’s Limited Area Prediction System (LAPS). Investigation of the LAPS atmospheric water balance, including comparison of the forecast precipitation to analyzed rain gauge observations, indicates that the LAPS forecasts capture the general qualitative features of the water balance. The key features of the atmospheric water balance over the Murray–Darling Basin are small atmospheric moisture flux divergence (at daily to annual time scales) and extended periods during which the atmospheric water balance terms are largely inactive, with the exception of evaporation, which is consistent and very large in summer. These features present unique challenges for NWP modeling. For example, the small moisture fluxes in the basin can easily be obscured by the systematic errors inherent in all NWP models. For the LAPS model forecasts, there is an unrealistically large evaporation excess over precipitation (associated with a positive bias in evaporation) and unexpected behavior in the moisture flux divergence. Two global reanalysis products (the NCEP Reanalysis I and the 40-yr ECMWF Re-Analysis) also both describe (physically unrealistic) long-term negative surface water budgets over the Murray–Darling Basin, suggesting that the surface water budget cannot be sensibly diagnosed based on output from current NWP models. Despite this shortcoming, numerical models are in general the most appropriate tool for examining the atmospheric water balance over the Murray–Darling Basin, as the atmospheric sounding network in Australia has extremely low coverage.

scholarly journals YEAST IN SOUTHWEST MONSOON RAINWATER

2020 ◽  
Vol 3 (3) ◽  
pp. 4-8
Author(s):  
SHEELA PAL
Keyword(s):  
Phase Contrast ◽  
Monsoon Rainfall ◽  
Southwest Monsoon ◽  
Yeast Cells ◽  
Successful Isolation ◽  
Tentative Model ◽  
Bacteria And Fungi ◽  
Southwest Monsoon Rainfall ◽  
Ascomycetous Yeasts ◽  
Extreme Care

Strong evidence of the presence of bacteria and fungi in the tropospheric boundary layer is available in the literature. We report successful isolation of unique morphotypes of wild ascomycetous yeasts from rainwater samples collected directly in sterile containers, taking extreme care to avoid ambient contamination. Direct and quick visualization of fresh rainwater samples under a phase contrast microscope indicated the sporadic presence of yeast cells. Further confirmation of the presence of yeast was obtained by plating of rainwater on a medium with antibiotics to generate pure colonies. We described their characteristics while molecular identification revealed it as Candida tropicalis. Yeast species  could contribute valuable knowledge about yeast transportation in the atmosphere. However, knowledge is insufficient about the yeast deposited from the atmosphere and its transportation across the atmosphere. We report and discuss these interesting and exciting results which are useful in understanding the microbiological dimension of meteorology and the southwest monsoon rainfall in the light of present discourse on global warming and climate change. We offer a tentative model for a possible source, role, and fate of the yeasts in rainwater.

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