Assessing recent impacts of climate change on design water requirement of Boro rice season in Bangladesh

Abstract

Water requirement is sensitive to the impacts of climate change, especially in Bangladesh because of limited freshwater availability in the dry season, despite the fact that the country's agriculture sector requires large quantities of water for the crop production. Hence, gaining a better understanding of changes in water requirements in Bangladesh during dry periods is important in the management of agricultural water resources. This study assesses the recent impacts of climate change on the design water requirement (DWR) of the Boro rice-growing season in Bangladesh using a frequency analysis over a 5-year period. The reference evapotranspiration (ET ref ), crop evapotranspiration (ET p ), effective rainfall (ERF), and gross irrigation water requirements (GIWR) of Boro rice were estimated based on daily weather data for the period of 1984-2013 using the CROPWAT8.0 model. The results showed the significant decreasing trends of ET ref in most of these Boro rice growth stages in all districts. The GIWR of Boro rice and its trends demonstrated significant spatial heterogeneity in the last three decades due to significant changes in the ERF and ET p . The DWR of Boro rice-growing season also supported the results of the GIWR, and the Weibull probability distribution function (PDF) is found to be an optimal PDF among eight PDFs for the estimation of DWR. Overall, the results indicate that a recent climate change does not only contribute to high water demands for the crop but also result in decrease water requirements due to variations in wind speed, sunshine hours, and relative humidity.

Are meteorological factors enhancing COVID-19 transmission in Bangladesh? Novel findings from a compound Poisson generalized linear modeling approach

“…Bangladesh Meteorological Department (BMD) has 43 weather stations across the country. The daily minimum temperature ( T min ) (°C), maximum temperature ( T max ) (°C), day relative humidity (DRH) (%), night relative humidity (NRH) (%), and rainfall (mm) datasets of 43 stations from March 8 to April 30, 2020 were collected from BMD (Islam et al 2019 , 2020a ). Diurnal temperature (TDN) (°C) and mean temperature (MT) were calculated from T min to T max .…”

“…(Rahman and Islam 2019 ; Salam and Islam 2020 ; Saha et al 2020 ). In this study, a RF model was used followed by Rahman an Islam et al ( 2019 ), Salam and Islam ( 2020 ), Saha et al ( 2020 ), Islam et al ( 2020b ) to explore the importance degree of climatic variables influencing COVID-19 mortality cases across eight major divisional cities of Bangladesh.…”

COVID-19 pandemic, dengue epidemic, and climate change vulnerability in Bangladesh: Scenario assessment for strategic management and policy implications

“…Bangladesh has been considering as one of the most vulnerable countries and a set of the climate change impacts have already been identified such as extreme temperature, erratic rainfall, salinity intrusion, sea-level rise, and increased intensity of floods, flash floods, droughts, and cyclones ( Islam et al, 2019 ; Rahman and Islam, 2019 ). And these hazards have significant negative impacts on livelihoods, food and nutritional security, water and sanitation and overall on public health.…”

The optimal alternative for quantifying reference evapotranspiration in climatic sub-regions of Bangladesh

“…Two distinct processes (evaporation and transpiration) happen concurrently, and there is no alternative way of differentiating one from the other. ET is one of the basic elements of the water cycle, and its estimation is necessary to drought mitigation and management as well as other fields, including agro-meteorology, hydrology, climatology, and environmental studies [2][3][4][5] . For this reason, many drought indices such as Reconnaissance Drought Index (RDI) 6 , Standardized Precipitation Evapotranspiration Index (SPEI) 7 , and the Water Surplus Variability Index (WSVI) 8 are based on the ET.…”

“…One ideal example is that Hargreaves and Samani 12 used the term "ETp" whereas again Hargreaves and Samani 13 applied the term "ET o ". Under the well-known background of global warming in recent decades, the term ET o has been broadly applied in hydrology [14][15][16] , agronomy field [17][18][19] , irrigation engineering 4,20,21 and meteorological field 22,23 . The application of ET o is also used in the studies of crop water demand.…”