The state of the art about drought monitoring in Turkey observed by the new satellite-based techniques


Okay Ahi G.

XXIX INTERNATIONAL SYMPOSIUM ON MODERN TECHNOLOGIES, EDUCATION AND PROFESSIONAL PRACTICE IN GEODESY AND RELATED FIELDS, İstanbul, Turkey, 5 - 06 November 2019, pp.24-33

  • Publication Type: Conference Paper / Full Text
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.24-33

Abstract

Drought is a long-lasting shortage in water supply in the atmosphere, surface and groundwater

expressing itself with (i) less than average precipitation (meteorological drought), (ii) followed

by a damage in crop production or in the ecology, if below-average precipitation period is

extended (agricultural drought) and also with (iii) significant fall of water reserves such as in

aquifers, lakes (hydrological drought). Thus, drought monitoring is crucial for the economy and

water resources management for a country, however, it cannot be achieved properly in national

scale with the traditional observation methods. Satellite-based techniques for drought

monitoring are very promising for this purpose. In this study, by using Center for Space

Research (CSR)’s Level 3, Release 5 (RL05) data observed by Gravity Recovery and Climate

Experiment (GRACE) satellite, German Research Center (GFZ)’s Level 3, Release 6 (RL06)

data observed by GRACE/GRACE-FO (GRACE-Follow-On) satellite, Tropical Rainfall

Measuring Mission (TRMM) precipitation data, Global Land Data Assimilation System

(GLDAS) data and finally drought indices (El Niño–Southern Oscillation: ENSO, North

Atlantic Oscillation: NOA, Self-calibrating Palmer Drought Severity index: SCPDSI), a state

of the art about drought monitoring in Turkey, is presented. The results propose to find answers

about how to reveal the dominant drought periods, get notable information about the spatial

distribution, observe spatial and temporal change rate and understand several prominent reasons

of the drought events observed in Turkey. Moreover, the results of the statistical approach used

for the prediction of GRACE/GRACE-FO derived Total Water Storage (TWS) time series is

discussed. According to our results, the spatial distribution of the drought is primarily affected

by the precipitation history but also by uncontrolled human usage of water resources, especially

in Central Anatolia according to GRACE and GRACE-FO results. The contrast leading to a

spatial change from Eastern part to Western part, with a rate of 1 cm/yr, is less obvious

according to GRACE-FO derived amplitude of TWS section. Recent, GRACE-FO amplitude

sections of TWS shows in the general sense, the increasing impact of drought observed in

Turkey.