Estimating spatial distribution of aridity and moisture indices of Mongolia using remotely sensed time series data

Erdenesukh Sumiya,Munkhdulam Otgonbayar,Renchinmyadag Tovuudorj

doi:10.5564/pmas.v61i01.1558

Abstract

The aim of this study is to estimate the spatial distribution of aridity and moisture indices using remotely sensed time-series data. For the analysis, we have chosen two simple climatic indices. One of two indices was the De Martonne aridity index, and the other one was the Mezentsev moisture index. The study area covers the total territory of Mongolia (~1.566 × 106 km2). Both indices could be estimated from meteorological station-based air temperature and precipitation. However, meteorological station-based recorded precipitation and temperature data with long coverage are only available from a limited number of stations with insufficient spatial coverage. In other words, these datasets suffer from uneven geographic coverage, with many areas of the Earth poorly represented. In this study, therefore, we have used satellite-derived temperature and precipitation data. Monthly mean air temperature has been estimated from MODIS LSTd, LSTn, and elevation using RF regression. Precipitation data has been extracted from Climate Hazards Group Infra-Red Precipitation with Station (CHIRPS) datasets. CHIRPS is gauge-satellite combined precipitation data. Based on De Martonne and Mezensev formulas, and satellite-derived meteorological data, spatial distribution maps of aridity and moisture indices in Mongolia were generated. The study result showed that aridity was observed in all areas of southern Mongolia, and some areas in the west, and grassland areas in the east, which is largely included in the dry steppe, desert-steppe, and gobi desert zones. Moisture was observed in the forest and forest-steppe areas in north, central, northeastern, and eastern Mongolia. A comparison of the aridity index and moisture index shows the following: of the total territory, aridity is 31.9:31.4 percent, humidity 14.7:13.4 percent respectively. Dry steppe, desert steppe, and Gobi desert zones are extremely sensitive to water resource variability and availability.

Highlights

The climate is a natural resource serving as a basis for many kinds of socio-economic activities
The results showed that about 25.5 percent and 29.1 percent of the entire area is classified as arid climate by the de Martonne aridity and Mezentsev moisture indices, respectively
We have estimated spatial distribution aridity and moisture indices over Mongolia derived from satellite-based time series temperature and precipitation data for the period 2002-2017

Summary

Introduction

The climate is a natural resource serving as a basis for many kinds of socio-economic activities. Several researchers have estimated the spatial distribution and spatial-temporal change in the aridity of Mongolia, using the meteorological station-measured temperature and precipitation data based on aridity equations. Nyamtseren, Feng, Deo [22] estimated spatiotemporal variations of four different indices over Mongolia, using climatic data from 70 weather stations for the period 1961-2015. Munkhdulam, Avirmed, and Sainbayar [23] estimated spatial distribution of three different indices: hydrothermal coefficient by Selyaninov, biological effectiveness index by Ivanov, and bioclimatic potential by Shashko over Mongolia using climatic data from some meteorological stations and posts, land surface temperature of the MODIS (Moderate Resolution Imaging Spectroradiometer), and precipitation data of the TRMM (Tropical Rainfall Measure Mission) for the period 20002014. The aim of this study is to estimate the spatial distribution of aridity and moisture indices using remotely sensed time-series data

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Conclusion