Getis-Ord Gi* statistics for hydrocarbons content analysis in the Tromjegan river basin

The information content and effectiveness of ecological research of the territory can be improved using the methods of multivariate analysis and mapping of the results. The article presents the analysis and mapping results of spatial and temporal trends of hydrocarbon pollution in the Tromjegan river basin for the period 2006–2018 using the tools of ArcGIS Pro. The informational and basic research is the data of local environmental monitoring of licensed blocks of the Khanty-Mansiysk Autonomous Okrug — Ugra. Pollution analysis was carried out on the basis of a detailed study of the geography of the source data using statistical calculations (minimum, average, maximum distances between sampling points, Getis-Ord Gi* index). Thematic maps were constructed using data averaged over the year. The spatial and temporal dynamics of hydrocarbons concentration in surface waters for 2006–2018 is analyzed using the “Hot Spot Analysis” tool. A temporary cluster section of hydrocarbons average annual concentration according to the Getis-Ord Gi* indicator allowed us to identify trends in the dynamics of indicators. Maps of hydrocarbons average annual concentration were compiled and the results of a spatial-temporal analysis of hydrocarbons average annual concentration in surface waters were presented. The identification of patterns in large arrays of long-term data and the consideration of the spatial component are necessary elements of modern environmental research. Analysis of the time series of average annual concentrations in the Tromjegan river basin showed a clear trend in the dynamics of hydrocarbon pollution. The findings can be the basis for making managerial decisions in the environmental monitoring of licensed blocks of the Khanty-Mansiysk Autonomous Okrug — Ugra.

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Emerging hot Spot Analysis and the Spatial-temporal Trends of NDVI in the Jing River Basin of China

10.21203/rs.3.rs-482991/v1 ◽

2021 ◽

Author(s):

Bin Xu ◽

Bin Qi ◽

Kai Ji ◽

Zhao Liu ◽

Lin Deng ◽

...

Keyword(s):

Land Cover ◽

River Basin ◽

Water Conservation ◽

Hot Spot ◽

Temporal Trends ◽

Soil And Water Conservation ◽

Vegetation Coverage ◽

Cold Spot ◽

The Loess Plateau ◽

Soil And Water

Abstract As an important indicator of vegetation coverage, the Normalized Difference Vegetation Index (NDVI) reflects the changing pattern and evolving trend of the environment. In the Loess Plateau, vegetation plays a critical role in soil and water conservation, which strongly affects the achievement of sustainable development goals. The study of the spatial distribution and temporal trends of NDVI is of great practical importance for the planning of soil and water conservation measures, the evaluation of environmental situation. In this study, the NDVI, precipitation and land cover data of the Jing River Basin were collected, the emerging hot spot and cold spot patterns of NDVI were examined, the characteristics of spatial distribution and temporal variation of the NDVI in the basin were analyzed, the impacts on NDVI changes from climate, land cover change have been discussed. The results show that the NDVI in Jing River Basin shows a spatial trend of decreasing from northwest to southeast. The emerging hot spot analysis results show that diminishing cold spot, oscillating hot spot, intensifying hot spot are predominant patterns in the basin. The whole basin shows the statistically significant upward trend of high-value aggregation of NDVI. The temporal trend of NDVI in the basin varies from-0.0171 to 0.0185 per year. The increasing trend of vegetation coverage in the basin is statistically significant. The positive correlation between the NDVI and the precipitation mainly observed upstream of the basin, revealing that the growth of vegetation in the Loess Plateau is more dependent on the water supply from the precipitation. Land cover transition patterns and the land use patterns also impact the spatial-temporal trends of the vegetation coverage in the basin. The study results may helpful for the vegetation restoration, soil and water conservation and sustainable development of the Jing River Basin.

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Groundwater dynamics in the Betwa River catchment in Central India

10.5194/egusphere-egu21-15373 ◽

2021 ◽

Author(s):

Niranjan Naik ◽

Zafar Beg ◽

Amit Kumar ◽

Kumar Gaurav

Keyword(s):

River Basin ◽

Groundwater Level ◽

Hot Spot ◽

Temporal Trends ◽

Central India ◽

Groundwater Depletion ◽

Groundwater Storage ◽

Groundwater Dynamics ◽

Freshwater Resource ◽

Storage Change

Groundwater is an important natural freshwater resource and plays a significant role in the socio-economic development of any country. The Betwa River basin in central India has experienced severe exploitation of groundwater resource in the past few decades. About 80 % of groundwater in this region is extracted for the agriculture purpose. Also, the scarcity in rainfall throughout the year and seasonal flow in the Betwa River has increased the agricultural dependence on the groundwater. This has led the Betwa River basin into a major hot spot of groundwater depletion.This study estimates the trend of groundwater level and storage change to assess the groundwater dynamics in the Betwa River basin. We used in-situ groundwater level data for a period between 1987-2018 to calculate the trend in groundwater level using the Seasonal and Trend decomposition using Loess (STL) method. Further, we performed the Ordinary Kriging to understand the spatial and temporal trends of groundwater during the pre-monsoon and post-monsoon. Eventually, we use the water table fluctuation (WTF) method to estimate groundwater storage in the study area. Our results suggest a decline in groundwater storage change as 701 and 626 MCM in the post and pre-monsoon period respectively from 2008-2018. During the same period, we observed that the Betwa basin has experienced about 3-5 m decline in the groundwater level.&#160;

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