scholarly journals Analysis of changes in climatological condition: a perspective from Barguna district of Bangladesh

2017 ◽  
Vol 5 (2) ◽  
pp. 133
Author(s):  
Tapos Kormoker ◽  
Ram Proshad ◽  
Mohammed Mahmud Khan ◽  
Bidhan Chandra Saha
Keyword(s):  
Missing Values ◽  
Small Time ◽  
Annual Rainfall ◽  
Measured Temperature ◽  
Secondary Sources ◽  
Average Maximum ◽  
Macro Scale ◽  
Long Term Changes ◽  
Significant Change

This study investigated the long-term changes in climatological condition, such as temperature, rainfall, humidity, storms, and tidal surge and flooding in Barguna district of Bangladesh. The BMD (Bangladesh Meteorological Department) data were used for temperature, rainfall, and humidity. The data for storms have been collected from secondary sources i.e. various journals, website and various records. This study applied the time series statistical test to examine the long-term changes in climatological condition, such as temperatures (1970-2015), rainfall (1975-2013), humidity (1975-2013), and storms (1987-2007). A parametric technique of trend analysis was used in this study for its inclusive use and simplicity. Data screening and filling missing values were also done before the analyses. The analyses of measured temperature indices that the annual average maximum and minimum mean temperature has increased 1.16°C and 0.56°C respectively at the end of 2015 since 1982 indicating that the weather has been becoming hotter. The analysis of the last 30 years rainfall data of Barguna was compared with national total annual rainfall and no significant change observed. The number of wetter days has been increasing over the time and more rainfall has been happening within small time. There is also a significant change in relative humidity. A total of thirty-five depressions, storms and cyclones hit Barguna district during the last 130 years among which hard hit severe cyclones have occurred in 1935, 1965, 1970 and the most recent cyclone SIDR in 2007 was notable. The study found that storm surge level and surge induced coastal flooding reached from the outfall of Baleshwar River up to 50 km upstream at Morrelganj with high surge level. Therefore, this study will provide a condensed view in further studies in advanced statistical modeling in combination with future scenario analysis for micro and macro scale climate variable changes in Bangladesh.

scholarly journals Long-term changes of weather stimuli based on the example of the southern part of Warsaw – Ursynów

2019 ◽  
Vol 28 (1) ◽  
pp. 25-34
Author(s):  
Katarzyna Rozbicka ◽  
Martyna Zawistowska
Keyword(s):  
Thermal Stress ◽  
Air Temperature ◽  
Significant Trend ◽  
Weather Station ◽  
Average Daily Temperature ◽  
Average Maximum ◽  
Long Term Changes ◽  
Frequency Changes ◽  
Thermal Stimuli

The aim of the work is to evaluate thermal sensations based on the average daily temperature of air and to determine thermal stimuli, using interdependent variability of air temperature (average, maximum and minimum). The data from the weather station Ursynów – SGGW was used for the analysis in the period 1961–2016. The analysis showed that with the highest frequency (74%) there are thermal sensations “saving” (“slightly cold”, “cool”, “warm”). In the case of thermal stimuli with the greatest frequency, changes from day to day were described as “neutral”, not exceeding 2°C . Based on the analysis of the long-term period trend of the number of days in the year, it can be stated an increase in the number of days with the thermal stress “very warm”, which is results from a positive statistically significant trend and also a decrease in number of days with thermal stimuli “sharp”.

Long-term changes in annual rainfall patterns in southern Israel

1994 ◽  
Vol 49 (2) ◽  
pp. 59-67 ◽  
Author(s):  
T. Ben-Gai ◽  
A. Bitan ◽  
A. Manes ◽  
P. Alpert
Keyword(s):  
Annual Rainfall ◽  
Long Term Changes ◽  
Rainfall Patterns

scholarly journals Long-Term Changes of Aquatic Invasive Plants and Implications for Future Distribution: A Case Study Using a Tank Cascade System in Sri Lanka

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 31
Author(s):  
Champika S. Kariyawasam ◽  
Lalit Kumar ◽  
Benjamin Kipkemboi Kogo ◽  
Sujith S. Ratnayake
Keyword(s):  
Sri Lanka ◽  
Climate Variability ◽  
Annual Rainfall ◽  
Trend Test ◽  
P Value ◽  
Positive Trend ◽  
Cascade System ◽  
Landsat Images ◽  
Long Term Changes

Climate variability can influence the dynamics of aquatic invasive alien plants (AIAPs) that exert tremendous pressure on aquatic systems, leading to loss of biodiversity, agricultural wealth, and ecosystem services. However, the magnitude of these impacts remains poorly known. The current study aims to analyse the long-term changes in the spatio-temporal distribution of AIAPs under the influence of climate variability in a heavily infested tank cascade system (TCS) in Sri Lanka. The changes in coverage of various features in the TCS were analysed using the supervised maximum likelihood classification of ten Landsat images over a 27-year period, from 1992 to 2019 using ENVI remote sensing software. The non-parametric Mann–Kendall trend test and Sen’s slope estimate were used to analyse the trend of annual rainfall and temperature. We observed a positive trend of temperature that was statistically significant (p value < 0.05) and a positive trend of rainfall that was not statistically significant (p values > 0.05) over the time period. Our results showed fluctuations in the distribution of AIAPs in the short term; however, the coverage of AIAPs showed an increasing trend in the study area over the longer term. Thus, this study suggests that the AIAPs are likely to increase under climate variability in the study area.

Decadal changes in mean annual rainfall drive long-term changes in bush-encroached southern African savannas

2016 ◽  
Vol 41 (6) ◽  
pp. 690-700 ◽  
Author(s):  
Munyaradzi D. Shekede ◽  
Amon Murwira ◽  
Mhosisi Masocha ◽  
Fadzai M. Zengeya
Keyword(s):  
Annual Rainfall ◽  
Mean Annual Rainfall ◽  
Long Term Changes

scholarly journals Farmers’ Perceptions of Climate Change, Long-term Variability and Trends in Rainfall in Apac District, Northern Uganda

2021 ◽  
Author(s):  
Francis Atube ◽  
Geoffrey M. Malinga ◽  
Martine Nyeko ◽  
Daniel M. Okello ◽  
Basil Mugonola ◽  
...  
Keyword(s):  
Climate Change ◽  
Abrupt Change ◽  
Smallholder Farmers ◽  
Change Points ◽  
Annual Rainfall ◽  
The Past ◽  
Rainfall Trends ◽  
Long Term Changes ◽  
Cropping Seasons

Abstract Background: Climate change poses a serious threat to agricultural livelihoods and food security of smallholder farmers in Sub Saharan Africa. Understanding long-term rainfall trends of variability and extremes at local scales and perceptions regarding long-term changes in climate variables is important in planning appropriate adaptation measures to climate change. This paper examines the perception of farmers in Apac district regarding long-term changes in climate variables and analyzes the trend of occurrence in seasonal and annual rainfall in Apac district, northern Uganda. A cross-sectional survey design was employed to collect data on perception of farmers regarding long-term changes in climate from 260 randomly selected small-holder farmers’ households across two sub-counties in Apac district by the administration of semi-structured questionnaires in February 2018. Monthly rainfall data sets from the Uganda Meteorological Authority (UMA) for the period 1980 to 2019 for the Apac district were also used to analyze trends of occurrences in seasonal and annual rainfall in the study area. The nonparametric Sequential Mann-Kendall (SMK) and Sequential SMK tests were employed at a 5% significance level to detect trends and abrupt change points in mean seasonal rainfall. Results: The majority of the respondents (87%) perceived a decrease in precipitation over the past 39 years. The plot of forward regression u(ti) values and backward regression u’(ti) values showed interactions indicating rainfall trends: rainfall lower and upper limits and abrupt change points in the different cropping seasons. Analysis of historical series of mean monthly and annual rainfall showed an abrupt change in rainfall in March, April, May (MAM) season in 1982. Although the September, October and November (SON) season did not show an abrupt significant change, there was a significant (p<0.05) increase in rainfall above the upper limit from 1994 to date. Conclusion: The mean seasonal rainfall for MAM and SON cropping seasons in the Apac district were highly variable from different time points within the past 39 years (1980-2019), while JJA did not realize a significant change in rainfall within the same study period. Thus, the two cropping seasons (MAM and SON) in the district experienced remarkable variations in rainfall. This, therefore, provides a basis for Government to strengthen the provision of an effective climate tailored agricultural advisory service to aid farmers’ adaptation planning at the local level and to assist smallholder farmers and land-use managers in developing effective adaptation management strategies to the effects of climate change.

scholarly journals Differential Signal of Change Among Multiple Components of West African Rainfall

2021 ◽  
Author(s):  
Omon Aigbovboise Obarein ◽  
Cameron C. Lee
Keyword(s):  
Rainfall Intensity ◽  
Climate Models ◽  
Grid Point ◽  
Congo Basin ◽  
Annual Rainfall ◽  
Reanalysis Dataset ◽  
Rainfall Frequency ◽  
Hourly Rainfall ◽  
Long Term Changes

Abstract Rainfall components likely differ in the magnitude and direction of their long-term changes for any given location, and some rainfall components may carry a greater regional signal of change than rainfall totals. This study evaluates the magnitude of change of multiple rainfall components relative to other components, and the greatest regions of change across all rainfall components in West Africa. Hourly rainfall data from the ERA5 reanalysis dataset was used to derive twelve rainfall components, which were evaluated for long-term means, interannual variability, and long-term changes. For rainfall totals and rainfall intensity, the central Sahel is witnessing increasing trends while the western Sahel is experiencing significant decreasing trends. In general, decreasing trends predominate in the study domain, especially in the northwestern Congo Basin, where annual rainfall is decreasing by 120mm per decade. Importantly, rainfall frequency accounts for 49% of all significant grid-point trends for the whole domain. In contrast, rainfall totals account for 26% of all combined significant trends across the domain, while rainfall intensity (12.6%), rainy season length (9.5%), and seasonality (3.3%) account for the remaining signals of change. Most of the changes among the rainfall components are in the Tropical Wet and Dry regions (59% of all significant trends); the Saharan and Equatorial regions account for the least changes. This study finds evidence that rainfall frequency is changing more across the regions compared to rainfall totals and should be explored as rainfall inputs in climate models to potentially improve regional predictions of future rainfall.

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