scholarly journals Spatio-temporal variability of climatic parameters across different altitudes of North- Western Himalaya

2021 ◽  
Vol 21 (3) ◽  
pp. 297-306
Author(s):  
PANKAJ PANWAR ◽  
SHARMISTHA PAL ◽  
NANCY LORIA ◽  
MED RAM VERMA ◽  
N.M. ALAM ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Management Strategies ◽  
Extreme Rainfall ◽  
Western Himalaya ◽  
Farming System ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Rainfall Occurrence ◽  
Spatio Temporal ◽  
Different Altitudes

Climate change impact varies across different altitudinal ranges and demands local specific management strategies for water resource and farming system management. The present study analyses spacio-temporal climate parameters across different altitudes of Himachal Pradesh a hilly state of India. Analysis shows that annually, minimum temperature has significantly decreased by -0.09°C at altitude I (350 - 400 m) while maximum temperature has significantly increased by 0.05°C at altitudes I and II (1400-1500 m) and decreased significantly by -0.08°C at altitude III (2000- 2100 m). Higher regions Altitude – IV (2900-3000 m) received lowest rainfall (746.1 mm) with 30.2 % variation. Seasonal rainfall variability was higher in post monsoon (102 - 174%) and least in monsoon (21 - 57%). Annual rainfall at altitude I is strongly irregular (PCI 20.1 to 22.3), followed by altitude – IV (PCI 15-25); altitude – II irregular (PCI 15-20) and altitude – III moderate to irregular (PCI 12 -19) rainfall. Seasonal Index values for four altitudes fall between 0.91-0.96 revealed that rainfall is irregular and markedly seasonal with longer drier season. Higher wavelet powers in altitude - I and II after 2005 suggests frequency of extreme rainfall occurrence had increased.

scholarly journals Spatio-Temporal Variability and Trend of Rainfall and Its Association with Pacific Ocean Sea Surface Temperature in West Harerge Zone, Eastern Ethiopia

2020 ◽  
Author(s):  
Getachew Bayable Tiruneh ◽  
Gedamu Amare ◽  
Getnet Alemu ◽  
Temesgen Gashaw
Keyword(s):  
Pacific Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Temporal Variability ◽  
Rainfall Variability ◽  
Sea Surface ◽  
Annual Rainfall ◽  
Eastern Ethiopia ◽  
Spatio Temporal ◽  
Annual Time

Abstract Background: Rainfall variability is a common characteristic in Ethiopia and it exceedingly affects agriculture particularly in the eastern parts of the country where rainfall is relatively scarce. Hence, understanding the spatio-temporal variability of rainfall is indispensable for planning mitigation measures during high and low rainfall seasons. This study examined the spatio-temporal variability and trends of rainfall in the West Harerge Zone, eastern Ethiopia.Method: The coefficient of variation (CV) and standardized anomaly index (SAI) was employed to analyze rainfall variability while Mann-Kendall (MK) trend test and Sen’s slop estimator were employed to examine the trend and magnitude of the rainfall changes, respectively. The association between rainfall and Pacific Ocean Sea Surface Temperature (SST) was also evaluated by the Pearson correlation coefficient (r).Results: The annual rainfall CV ranges from 12-19.36% while the seasonal rainfall CV extends from 15-28.49%, 24-35.58%, and 38-75.9% for average Kiremt (June-September), Belg (February-May), and Bega (October-January) seasons, respectively (1983-2019). On the monthly basis, the trends of rainfall decreased in all months except in July, October, and November. However, the trends of rainfall were not statistically significant (α = 0.05), unlike November. The annual rainfall trends showed a non-significant decreasing trend. On a seasonal basis, the trend of mean Kiremt and Belg seasons rainfall was decreased. But, it increased in Bega season although it was not statistically significant. Moreover, the correlation between rainfall and Pacific Ocean SST was negative for Kiremt while positive for Belg and Bega seasons. Besides, the correlation between rainfall and Pacific Ocean SST was negative at annual time scales.Conclusions: High spatial and temporal rainfall variability on monthly, seasonal, and annual time scales was observed in the study area. Seasonal rainfall has high inter-annual variability in the dry season (Bega) than other seasons. The trends in rainfall were decreased in most of the months. Besides, the trend of rainfall was increased annually and in the Bega season rather than other seasons. Generally, the occurrence of droughts in the study area was associated with ENSO events like most other parts of Ethiopia and East Africa.

Biogeographical effects on body mass of native Australian and introduced mice, Pseudomys hermannsburgensis and Mus domesticus: an inquiry into Bergmann's Rule

2008 ◽  
Vol 56 (6) ◽  
pp. 423 ◽  
Author(s):  
Sean Tomlinson ◽  
Philip C. Withers
Keyword(s):  
Ambient Temperature ◽  
Body Mass ◽  
Rainfall Variability ◽  
Negative Influence ◽  
Bergmann’S Rule ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Mus Domesticus ◽  
Arid Areas ◽  
Bergmann's Rule

We investigated interactions of body mass with geographical location, and five climatic measures for two Australian rodents, the native Australian sandy inland mouse (Pseudomys hermannsburgensis) and the introduced house mouse (Mus domesticus). Correlation and regression analyses identified interactions of body mass with latitude, longitude, average highest maximum and lowest minimum temperatures, average annual rainfall, rainfall variability, and aridity. There was a significant correlation of body mass with latitude and longitude for Mus domesticus and P. hermannsburgensis. House mice were heavier in the south and east, and sandy inland mice were heavier in the north and east. M. domesticus conforms to Bergmann’s Rule, while P. hermannsburgensis does not. Maximum temperature, aridity and rainfall variability significantly influenced body mass of M. domesticus, which was heavier at cooler maxima, in less arid areas, and in areas of greater rainfall variability. Only aridity significantly influenced body mass of P. hermannsburgensis, which was heavier in more arid areas. Temperature did not interact significantly with body mass. After accounting for climatic variables, there was still a significant relationship between the residuals of body mass with locality for both species, with a negative influence of latitude and a positive influence of longitude in both; the latitudinal interaction for both species was converse to Bergmann’s Rule. We suggest that latitude, ambient temperature and other selection pressures (such as aridity or productivity) can act in opposing directions, and speculate that the influence of other factors, such as food availability or sociality, may be more important than latitude or ambient temperature.

scholarly journals Rainfall Variability across the Agro-Climatic Zones of a Tropical Highland: The Case of the Jema Watershed, Northwestern Ethiopia

Environments ◽  
2019 ◽  
Vol 6 (11) ◽  
pp. 118 ◽  
Author(s):  
Taye ◽  
Simane ◽  
Zaitchik ◽  
Selassie ◽  
Setegn
Keyword(s):  
Climate Variability ◽  
Coefficient Of Variation ◽  
Rainfall Variability ◽  
Arithmetic Functions ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Climatic Zones ◽  
Climate Indicators

The objective of the study was to analyze the variability of various climate indicators across the agro-climatic zones (ACZs) of the Jema watershed. The variability was analyzed considering mean annual rainfall (MARF, mm), mean daily minimum temperature (MDMinT, °C), and mean daily maximum temperature (MDMaxT, °C). A one-way analysis of variance (ANOVA) was employed to test whether group mean differences exist in the values of the indicated climatic indicators among the ACZs of the watershed. The coefficient of variation was computed to analyze the degree of climate variability among the ACZs. Rainfall and temperature data sets from 1983 to 2017 were obtained from nearby meteorological stations. The effect of climate variability in the farming system was assessed with reference to local farmers’ experience. Ultimately, the values of the stated indicators of exposure to climate variability were indexed (standardized) in order to run arithmetic functions. The MARF decreases towards sub-alpine ACZs. Based on the result of the ANOVA, the two-tailed p-value (≤ 0.04) was less than 0.05; that is, there was a significant variation in MARF, MDMaxT (°C), and MDMinT (°C) among the ACZs. The coefficient of variation showed the presence of variations of 0.18–0.88 for MARF, 0.18 to 0.85 for MDMaxT, and 0.02–0.95 for MDMinT across the ACZs. In all of the indicators of exposure to climate variability, the lowest and highest indexed values of coefficient of variation were observed in the moist–cool and sub-alpine ACZs, respectively. Overall, the aggregate indexed values of exposure to various climate indicators ranged from 0.13–0.89 across the ACZs. The level of exposure to climate variability increased when moving from moist–cool to sub-alpine ACZs. The overall crop diversity declined across the ACZs of the watershed. Nevertheless, mainly because of the rise in temperature, the climate became suitable for cultivating maize and tef even at higher elevations. In order to adapt to the inter-annual variability of the rainy season, the process of adapting early-maturing crops and the use of improved seeds needs to be enhanced in the watershed, especially in the higher-elevation zones. It is also essential to revise traditional crop calendars and crop zones across the ACSz.

scholarly journals Spatio-temporal rainfall trends in the twentieth century for Bundelkhand region, India

2017 ◽  
Vol 8 (3) ◽  
pp. 441-455 ◽  
Author(s):  
C. Jana ◽  
N. M. Alam ◽  
D. Mandal ◽  
M. Shamim ◽  
Rajesh Kaushal
Keyword(s):  
Monsoon Rainfall ◽  
Monsoon Season ◽  
Extreme Rainfall ◽  
Farming Systems ◽  
Temporal Analysis ◽  
Extreme Weather Events ◽  
Rainfall Trend ◽  
Rainfall Occurrence ◽  
Rainfall Trends ◽  
Spatio Temporal

Globally, climate change and extreme weather events are occurring more frequently, impacting water resources and farming systems. Therefore, spatio-temporal analysis of long-term rainfall is much needed to understand the variability of rainfall occurrence. The present study attempts to analyse spatio-temporal rainfall change scenarios in the 20th century (1901–2000) over Bundelkhand, one of the drought hit regions of India. Analysis shows that major rainfall contributed from 3 months, i.e. July, August and September. However, decreasing rainfall trend during monsoon season and increasing trend during pre-monsoon and post-monsoon season indicates the scenario of shifting rainfall from normal occurrence. This result is supported by decreasing seasonality index (SI) (1.94–1.1). The northern part of the region witnessed positive annual and monsoon rainfall trend but the southern part observed negative trend. Pettitt's test indicates 1983 is the most probable change year with 0.95 probability, after which annual and monsoon rainfall was found decreasing. Wavelet analysis revealed that extreme rainfall occurrence was observed with a periodicity of 2–16 years. However, Bundelkhand rainfall pattern depicts declining rainfall trends, heading towards a further drier phase with more irregular rainfall in the coming era. The study will serve as future reference in similar regions in the world to determine vital weather patterns which may impact farming systems.

scholarly journals Spatio-temporal Variability and Trends of Mean and Extreme Rainfall Events in the Sudano-sahelian Region of Cameroon

2021 ◽  
Author(s):  
Ibrahim NJOUENWET ◽  
Lucie A. Djiotang Tchotchou ◽  
Brian Odhiambo Ayugi ◽  
Guy Merlin Guenang ◽  
Derbetini A. Vondou ◽  
...  
Keyword(s):  
Climate Change ◽  
Extreme Rainfall ◽  
Temporal Variations ◽  
Annual Rainfall ◽  
Drought Risk ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Precipitation Concentration ◽  
Spatio Temporal ◽  
The Impact

Abstract The Sudano-Sahelian region of Cameroon is mainly drained by the Benue, Chari and Logone rivers, which are very useful for water resources, especially for irrigation, hydropower generation, and navigation. Long-term changes in mean and extreme rainfall events in the region may be of crucial importance in understanding the impact of climate change. Daily and monthly rainfall data from twenty-five synoptic stations in the study area from 1980 to 2019 and extreme indices from the Expert Team on Climate Change Detection and Indices (ETCCDI) measurements were estimated using the non-parametric Modified Mann-Kendall test and the Sen slope estimator. The precipitation concentration index (PCI), the precipitation concentration degree (PCD), and the precipitation concentration period (PCP) were used to explore the spatio-temporal variations in the characteristics of rainfall concentrations. An increase in extreme rainfall events was observed, leading to an upward trend in mean annual. Trends in consecutive dry days (CDD) are significantly increasing in most parts of the study area. This could mean that the prevalence of drought risk is higher in the study area. Overall, the increase in annual rainfall could benefit the hydro-power sector, agricultural irrigation, the availability of potable water sources, and food security.

scholarly journals Evaluation and Application of Multi-Source Satellite Rainfall Product CHIRPS to Assess Spatio-Temporal Rainfall Variability on Data-Sparse Western Margins of Ethiopian Highlands

2019 ◽  
Vol 11 (22) ◽  
pp. 2688 ◽  
Author(s):  
Ashebir Sewale Belay ◽  
Ayele Almaw Fenta ◽  
Alemu Yenehun ◽  
Fenta Nigate ◽  
Seifu A. Tilahun ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Daily Rainfall ◽  
Annual Rainfall ◽  
Integration Time ◽  
Spatial And Temporal Variability ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Mean Annual Rainfall ◽  
Time Space ◽  
Spatio Temporal

The spatio-temporal characteristic of rainfall in the Beles Basin of Ethiopia is poorly understood, mainly due to lack of data. With recent advances in remote sensing, satellite derived rainfall products have become alternative sources of rainfall data for such poorly gauged areas. The objectives of this study were: (i) to evaluate a multi-source rainfall product (Climate Hazards Group Infrared Precipitation with Stations: CHIRPS) for the Beles Basin using gauge measurements and (ii) to assess the spatial and temporal variability of rainfall across the basin using validated CHIRPS data for the period 1981–2017. Categorical and continuous validation statistics were used to evaluate the performance, and time-space variability of rainfall was analyzed using GIS operations and statistical methods. Results showed a slight overestimation of rainfall occurrence by CHIRPS for the lowland region and underestimation for the highland region. CHIRPS underestimated the proportion of light daily rainfall events and overestimated the proportion of high intensity daily rainfall events. CHIRPS rainfall amount estimates were better in highland regions than in lowland regions, and became more accurate as the duration of the integration time increases from days to months. The annual spatio-temporal analysis result using CHIRPS revealed: a mean annual rainfall of the basin is 1490 mm (1050–2090 mm), a 50 mm increase of mean annual rainfall per 100 m elevation rise, periodical and persistent drought occurrence every 8 to 10 years, a significant increasing trend of rainfall (~5 mm year−1), high rainfall variability observed at the lowland and drier parts of the basin and high coefficient of variation of monthly rainfall in March and April (revealing occurrence of bimodal rainfall characteristics). This study shows that the performance of CHIRPS product can vary spatially within a small basin level, and CHIRPS can help for better decision making in poorly gauged areas by giving an option to understand the space-time variability of rainfall characteristics.

scholarly journals Watershed-Based Rainfall variability and trends of extreme rainfall events in South East Awash Basin, Ethiopia

2019 ◽  
Vol 6 (6) ◽  
pp. 5524-5530
Author(s):  
Yonas Tadesse Alemu
Keyword(s):  
Coefficient Of Variation ◽  
Rainy Season ◽  
Rainfall Variability ◽  
Extreme Rainfall ◽  
Annual Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Precipitation Distribution ◽  
Precipitation Concentration ◽  
Dire Dawa

This study presents analysis of Rainfall variability and trends of extreme rainfall events in the Oda Gunufeta -Cherecha -Dechatu watershed, Awash Drainage Basin, Eastern Ethiopia. The study employed the coefficient of variation and the Precipitation Concentration Index (PCI) as statistical descriptors of rainfall variability. The indices at the five stations were subjected to non-parametric Mann-Kendall test to detect the trend over the period between 1985 to 2014. The results of the study revealed that, the watershed experiences moderate inter-annual rainfall variability. The Belg rainfall shows high variability than Kiremt rainfall. Highest Belg & Kiremt rainfall variability is observed in Dire Dawa with coefficient of variation of 46% and 40% respectively. The annual PCI for the watershed in all the stations under investigation during the record periods showed that 100% of the years for which the annual PCI was estimated fell within the irregular precipitation distribution range or high precipitation concentration. The irregular precipitation distribution also extended to all the stations in short rainy season (Belg rainfall) and in two stations in the main rainy season (Kiremt season). With regard to the rainfall trend, the annual rainfall has showed a negative trend in most of the stations for the period 1985-2014. The Mann–Kendall trend test during the Kiremt season shows a positive trend in Dengego, Dire Dawa, Combolcha and Haramaya and the increasing tendency is significant at p<0.1 in Degego, p<0.05 in Dire Dawa, p <0.05 in Combolcha and p <0.01 in Haramaya. The heavy rainfall events, the 90th & 95th percentiles, in all the five stations showed an increasing pattern but except in Combolcha the trends are not statistically significant. This implies that the watershed has been under increased rainfall intensity and this in turn has the potential cause for high risk of flood occurrences.

scholarly journals Analysis of spatio-temporal climate variability of a shallow lake catchment in Tanzania

2020 ◽  
Author(s):  
Latifa O. Nyembo ◽  
Isaac Larbi ◽  
Mwemezi J. Rwiza
Keyword(s):  
Water Productivity ◽  
Standardized Precipitation Index ◽  
Negative Influence ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Adaptation Measures ◽  
Distance Weighting ◽  
Spatio Temporal ◽  
Slope Estimator ◽  
Lake Catchment

Abstract This study analyzed the trends and spatio-temporal variability in rainfall and temperature, and the length of the rainy season (LRS) in the Lake Manyara catchment, Tanzania, covering a period between 1988 and 2018 using stations and satellite climate product. The Mann-Kendall statistical test, Sen's slope estimator, and inverse distance weighting interpolation techniques were used to detect the trends, magnitude of trends and spatial distribution of rainfall and temperature. A modified Stern's method and water balance concept were used for rainfall onset, cessation and LRS analysis, while a standardized precipitation index (SPI) was used to investigate the wetness or dryness of the area. The results showed high variability and decreasing trend (4 mm/y) in annual rainfall, and non-significant increasing trend for minimum and maximum temperature. Rainfall increased from the western to the northern part of the catchment whereas a reversal pattern was noticed for temperature. The SPI shows a signal of normal condition (about 65%) for all stations – with few years showing evidence of wetter and drier conditions. The LRS showed a decreasing trend indicating a potential negative influence on rain-dependent activities. There is a need, therefore, for adaptation measures such as improving water productivity and irrigation at the farm and catchment level.

scholarly journals Rainfall variability and floods occurrence in the city of Bamenda (Northwest of Cameroon)

2017 ◽  
Vol 11 (1) ◽  
pp. 65-82 ◽  
Author(s):  
Saha Frederic ◽  
Tchindjang Mesmin
Keyword(s):  
Rainfall Variability ◽  
Extreme Rainfall ◽  
Annual Rainfall ◽  
Annual Number ◽  
Extreme Rainfall Event ◽  
Average Profile ◽  
Flood Flows ◽  
Annual Distribution ◽  
Subsistence Activities ◽  
The City

Abstract This study is based on analysis of rainfall data from 1951-2010 collected at the climatic station of Bamenda. We also use the results of a questionnaire survey applied to 172 households in at-risk neighborhoods. The inventory of some cases of flooding that occurred in the city of Bamenda was done through focus groups. The appreciation of the socio-economic and demographic environment is based on surveys among Cameroonian Households by the National Institute of Statistics (NIS) and General Census of Population and Housing. Statistical examination revealed that annual rainfall in the city of Bamenda experienced a break in 1958. This break buckled the wettest decade of the series. After three decades of worsening, rainfall is experiencing rising since early 1990. The average profile of the annual distribution of rainfall shows a concentration of over 53% in 03 months (July, August and September). During these three months, the rivers of the city know their flood flows and populations in the valleys are affected. The analysis of the annual number of rainy days shows a downward trend and an increase of extreme rainfall event frequency (≥50mm in 24h). It is also apparent that more and more years are experiencing erratic distribution of their precipitation. Then, the perception of people is significantly reduced. Subsistence activities are also affected and development is facing new subtleties. In conclusion, the rainfall experienced strong variability in the city of Bamenda. This situation reinforces the risk of flooding by increasing flood water and increasing the vulnerability of populations.

Changing Spatio-Temporal Rainfall Fluctuation over North East India

2021 ◽  
pp. 373-381
Author(s):  
Leena K. Tribhuvan ◽  
Ganesh K. Chavhan
Keyword(s):  
Rainfall Variability ◽  
Tropical Meteorology ◽  
Annual Rainfall ◽  
Eastern Region ◽  
Desert Area ◽  
North East India ◽  
North East ◽  
The North ◽  
North Eastern ◽  
Spatio Temporal

This study is analysis of changes in rainfall fluctuation in North East India. Using the longest instrumental monthly rainfall data of well spread 316 stations across India available from Indian Institute of Tropical Meteorology (IITM), the fluctuation characteristics as well as the spatial-temporal variability of the seasonal, monsoon monthly and annual rainfall pattern over the north eastern region of India (NER) have been examined. On an average, NER receives about 2450 mm of rainfall with 1093.0 mm as its annual evapo transpiration. The winter (JF) rainfall contributes 2.1% to the annual rainfall; summer (MAM) rainfall 24.3%; summer monsoon (JJAS) rainfall 65.1% and the post-monsoon (OND) rainfall contributes 8.5% to the annual rainfall. The region shows great variation in surface temperature regime (15oC to 32oC in summer and 0 to 26oC in winter). The spatial-temporal rainfall variability shows random fluctuating characteristics of expansion / contraction of desert area but overall it is showing a slight decreasing over the NER as well as whole India.

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