scholarly journals Long Term Spatio-temporal Variations of Seasonal and Decadal Aridity in India

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
Pavan Kumar B ◽  
Bhavani Pinjarla ◽  
P K Joshi ◽  
P S Roy
Keyword(s):  
Water Resource Management ◽  
Arid Zone ◽  
Potential Evapotranspiration ◽  
Aridity Index ◽  
Temporal Variations ◽  
United Nations Environment Programme ◽  
Climate Data ◽  
Land Use Pattern ◽  
Changing Patterns ◽  
Spatio Temporal

A comprehensive analysis of climate data (1958-2018) is carried out at the national scale in India to assess spatiotemporal variation in aridity. The aridity is analyzed using UNEP (United Nations Environment Programme) Aridity Index (AI), which is the ratio between Precipitation (P) and Potential Evapotranspiration (PET). Freely available Terra-Climate database, P and PET variables, offered an unprecedented opportunity for monitoring variations in AI and aridity index anomalies (AIA) at interseasonal and inter-decadal basis. The study also assesses longer term patterns of P and AI anomalies with vegetation anomalies. The results indicate that significant clustered areas with maximum dryness are located at west-central part of India, the state of Maharashtra. Overall, there is a gradual increase in the extent of arid zone during 60-year period and spatially maximum extent of percentage change in aridity area is observed. The change patterns of AI in India are largely driven by the changing patterns of precipitation. The maximum impact of decline in precipitation on AIA was observed during Kharif season frequently, for every 4-5 years during 1972-1992. The pattern repeated in the last few recent years (2013- 2018), the decline in precipitation resulted increased aridity. The study also reveals that the availability and usage of irrigation sources have increased from 2014 to 2018. Thus, despite of less precipitation positive vegetation has been resulted in this period. The findings are important to understand the impacts of climate change on land use pattern, and land and water resource management.

scholarly journals Spatial-Temporal Variation of Aridity Index of China during 1960–2013

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Huiping Huang ◽  
Yuping Han ◽  
Mingming Cao ◽  
Jinxi Song ◽  
Heng Xiao
Keyword(s):  
Temporal Variation ◽  
Potential Evapotranspiration ◽  
Regional Climate ◽  
Aridity Index ◽  
Principal Component ◽  
Kendall Test ◽  
Semiarid Region ◽  
Climate Data ◽  
Gis Technology ◽  
Important Indicator

Aridity index, as the ration of potential evapotranspiration and precipitation, is an important indicator of regional climate. GIS technology, Morlet wavelet, Mann-Kendall test, and principal component analysis are utilized to investigate the spatial-temporal variation of aridity index and its impacting factors in China on basis of climate data from 599 stations during 1960–2013. Results show the following. (1) Boundaries between humid and semihumid region, and semihumid and semiarid region coincide with 400 mm and 800 mm precipitation contour lines. (2) Average annual aridity index is between 3.4 and 7.5 and shows decrease trend with a tendency of –0.236 per decade at 99% confidence level. (3) The driest and wettest month appear in December and July, respectively, in one year. (4) Periods of longitudinal and latitudinal shift of aridity index 1, 1.5, and 4 contours coordinate are 10 and 25 years, 6 and 26 years, and 5 and 25 years, respectively. (5) Four principal components which affect aridity index are thermodynamic factors, water and radiation factors, geographical and air dynamic factors, and evaluation factor, respectively.

scholarly journals Spatio-temporal characteristics of meteorological drought in Khyber Pakhtunkhwa, Pakistan

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249718
Author(s):  
Ghani Rahman ◽  
Atta-ur Rahman ◽  
Sami Ullah ◽  
Muhammad Dawood ◽  
Muhammad Farhan Ul Moazzam ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Aridity Index ◽  
Meteorological Drought ◽  
Meteorological Station ◽  
United Nations Environment Programme ◽  
Linear Regression Method ◽  
Detailed Knowledge ◽  
Khyber Pakhtunkhwa ◽  
The North ◽  
Spatio Temporal

This study analysed spatio-temporal fluctuations in rainfall to assess drought and wet spells in Khyber Pakhtunkhwa, Pakistan. Temporal changes in rainfall were assessed using a linear regression method, while aridity conditions at each meteorological station were measured using the United Nations Environment Programme climate aridity index. In this study, drought and wet spell patterns were identified using the Standardized Precipitation Evapotranspiration Index (SPEI). The Spearman’s Rho (SR) test was applied to find trends in the temporal 1-month and 12-month SPEI data. Balakot, Dir, Kakul, Kalam, Malam Jabba, Parachinar, Patan and Saidu were humid whereas Cherat and Timergara were sub-humid meteorological stations while Bannu, Chitral, Drosh and Peshawar were semi-arid and D.I. Khan was found to be the only arid meteorological station in the study area. The regression results revealed that the amount of rainfall is decreasing at Balakot, Kakul and Dir, while in the southern part of the province the amount of rainfall is increasing, such as in Parachinar and Cherat. The SPEI results revealed distinct drought spells in 1971–1974, 1984–1989, 1998–2004 and recently in 2017–2018, in almost all met-stations results. The SR results indicated a significant wet trend at met-station Parachinar, located in the west, while a significant drying trend has been noted at Balakot in the north-eastern part of the study area. Detailed knowledge about rainfall variability can provide a foundation for the planning and use of water resources.

scholarly journals Water table fluctuation and its effects on vegetation in a semiarid environment

2011 ◽  
Vol 8 (2) ◽  
pp. 3271-3304 ◽  
Author(s):  
L. Duan ◽  
T. Liu ◽  
X. Wang ◽  
Y. Luo ◽  
W. Wang ◽  
...  
Keyword(s):  
Water Table ◽  
Vegetation Index ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Depth Map ◽  
Northern China ◽  
Temporal Variations ◽  
Water Table Fluctuation ◽  
Semiarid Environment ◽  
Spatio Temporal

Abstract. A good understanding of water table fluctuation effects on vegetation is crucial for sustaining fragile hydrology and ecology of semiarid areas such as the Horqin Sandy Land (HSL) in northern China, but such understanding is not well documented in literature. The objectives of this study were to examine spatio-temporal variations of water table and their effects on vegetation in a semiarid environment. A 9.71 km2 area within the HSL was chosen and well-instrumented to continuously measure hydrometeorologic parameters (e.g., water table). The area comprises of meadow lands and sandy dunes as well as transitional zones in between. In addition to those measured data, this study also used Landsat TM and MODIS imageries and meteorological data at a station near the study area. The spatio-temporal variations were examined using visual plots and contour maps, while the effects on vegetation were determined by overlaying a water table depth map with a vegetation index map derived from the MODIS imageries. The results indicated that water table was mainly dependent on local topography, localized geological settings, and human activities (e.g., reclamation). At annual and monthly scales, water table was mainly a function of precipitation and potential evapotranspiration. A region within the study area where depth to water table was smaller tended to have better (i.e., more dense and productive) vegetation cover. Further, the results revealed that water table fluctuation was more sensitive for vegetations in the meadow lands than in the transitional zones, but it was least sensitive for vegetations in the sandy dunes.

scholarly journals Agroclimatic zonation of Tigray region of Ethiopia based on aridity index and traditional agro-climatic zones

2021 ◽  
Vol 21 (2) ◽  
pp. 176-181
Author(s):  
H. HAFTOM ◽  
A. HAFTU ◽  
K. GOITOM ◽  
H. MESERET
Keyword(s):  
Potential Evapotranspiration ◽  
Aridity Index ◽  
Climate Data ◽  
Climate Services ◽  
Climatic Zones ◽  
Tigray Region ◽  
Agroclimatic Zone ◽  
Elevation Model ◽  
Agroclimatic Zones ◽  
Semi Arid

The aim of this study was to identify the agroclimatic zones of Tigray region based on aridity index and traditional agroclimatic zone using 37-year (1981-2017) spatial climate data downloaded for Tigray region from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) for rainfall and from Enhancing National Climate Services (ENACTS) data for temperature. Arc map 10.3 was used for mapping of all climatic variables and zonation of agro-climatic zones. Potential evapotranspiration (PET) was computed based on Hargreaves formula and the aridity index was computed. Besides, the digital elevation model was downloaded from ASTER data. The aridity map of Tigray divided into three index zones (0.03-0.2, 0.2–0.5 and 0.5–0.65) and five traditional agro-climate zones (<1500,1500-2000,2000- 2500, 2500-3000, >3000 m.a.s.l.) were overlaid, which divided entire region of Tigray into fifteen agroclimatic zones. Hot semi-arid, warm semi-arid, tepid semi-arid and hot arid were the dominant zones in the region.

Spatio-temporal variations of winter wheat water requirement and climatic causes in Huang-Huai-Hai Farming Region

2012 ◽  
Vol 20 (3) ◽  
pp. 356-362 ◽  
Author(s):  
Xiao-Lin YANG ◽  
Zhen-Wei SONG ◽  
Hong WANG ◽  
Quan-Hong SHI ◽  
Fu CHEN ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Temporal Variations ◽  
Water Requirement ◽  
Spatio Temporal

Spatio-temporal Variations in Water Quality Parameter Trends in River Waters

2018 ◽  
Vol 69 (10) ◽  
pp. 2940-2952 ◽  
Author(s):  
Martina Zelenakova ◽  
Pavol Purcz ◽  
Radu Daniel Pintilii ◽  
Peter Blistan ◽  
Petr Hlustik ◽  
...  
Keyword(s):  
Water Quality ◽  
Chemical Oxygen Demand ◽  
Quality Indicators ◽  
Water Resource Management ◽  
Oxygen Demand ◽  
Temporal Variations ◽  
Water Quality Parameter ◽  
Agricultural Activity ◽  
Water Quality Indicators ◽  
Nitrite Nitrogen

Evaluating trends in water quality indicators is a crucial issue in integrated water resource management in any country. In this study eight chemical and physical water quality indicators were analysed in seven river profiles in the River Laborec in eastern Slovakia. The analysed water quality parameters were biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), pH, temperature (t), ammonium nitrogen (NH4+-N), nitrite nitrogen (NO2--N), nitrate nitrogen (NO3--N), and total phosphorus (TP). Data from the monitored indicators were provided by the Ko�ice branch of the Slovakian Water Management Company, over a period of 15 years from 1999 to 2013. Mann�Kendall non-parametric statistical test was used for the trend analysis. Biochemical and chemical oxygen demand, ammonium and nitrite nitrogen content exhibit decreasing trends in the River Laborec. Decreasing agricultural activity in the area has had a significant impact on the trends in these parameters. However, NO2--N was the significant parameter of water quality because it mostly exceeds the limit value set in Slovak legislation, Regulation No. 269/2010 Coll. In addition, water temperature revealed an increasing trend which could be caused by global increase in air temperature. These results indicate that human activity significantly impacts the water quality.

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