Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets

Understanding the spatio-temporal characteristics of water storage changes is crucial for Ethiopia, a country that is facing a range of challenges in water management caused by anthropogenic impacts as well as climate variability. In addition to this, the scarcity of in situ measurements of soil moi...

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Main Authors: Awange, Joseph, Gebremichael, M., Forootan, E., Wakbulcho, G., Anyah, R., Ferreira, V., Alemayehu, T.
Format: Journal Article
Published: Elsevier 2014
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/19765
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author Awange, Joseph
Gebremichael, M.
Forootan, E.
Wakbulcho, G.
Anyah, R.
Ferreira, V.
Alemayehu, T.
author_facet Awange, Joseph
Gebremichael, M.
Forootan, E.
Wakbulcho, G.
Anyah, R.
Ferreira, V.
Alemayehu, T.
author_sort Awange, Joseph
building Curtin Institutional Repository
collection Online Access
description Understanding the spatio-temporal characteristics of water storage changes is crucial for Ethiopia, a country that is facing a range of challenges in water management caused by anthropogenic impacts as well as climate variability. In addition to this, the scarcity of in situ measurements of soil moisture and groundwater, combined with intrinsic ‘‘scale limitations’’ of traditional methods used in hydrological characterization are further limiting the ability to assess water resource distribution in the region. The primary objective of this study is therefore to apply remotely sensed and model data over Ethiopia in order to (i) test the performance of models and remotely sensed data in modeling water resources distribution in un-gauged arid regions of Ethiopia, (ii) analyze the inter-annual and seasonal variability as well as changes in total water storage (TWS) over Ethiopia, (iii) understand the relationship between TWS changes, rainfall, and soil moisture anomalies over the study region, and (iv) identify the relationship between the characteristics of aquifers and TWS changes. The data used in this study includes; monthly gravity field data from the Gravity Recovery And Climate Experiment (GRACE) mission, rainfall data from the Tropical Rainfall Measuring Mission (TRMM), and soil moisture from the Global Land Data Assimilation System (GLDAS) model. Our investigation covers a period of 8 years from 2003 to 2011.The results of the study show that the western part and the north-eastern lowlands of Ethiopia experienced decrease in TWS water between 2003–2011, whereas all the other regions gained water during the study period. The impact of rainfall seasonality was also seen in the TWS changes. Applying the statistical method of Principal Component Analysis (PCA) to TWS, soil moisture and rainfall variations identified the dominant annual water variability in the western, north-western, northern, and central regions, and the dominant seasonal variability in the western, north-western, and the eastern regions. A correlation analysis between TWS and rainfall indicated a minimum time lag of zero to a maximum of six months, whereas no lag is noticeable between soil moisture anomalies and TWS changes. The delay response and correlation coefficient between rainfall and TWS appears to be related to recharge mechanisms, revealing that most regions of Ethiopia receive indirect recharge. Our results also show that the magnitude of TWS changes is higher in the western region and lower in the north-eastern region, and that the elevation influences soil moisture as well as TWS.
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spelling curtin-20.500.11937-197652019-02-19T04:26:27Z Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets Awange, Joseph Gebremichael, M. Forootan, E. Wakbulcho, G. Anyah, R. Ferreira, V. Alemayehu, T. Ethiopia Hydrological regimes GRACE-TWS changes Climate TRMM Understanding the spatio-temporal characteristics of water storage changes is crucial for Ethiopia, a country that is facing a range of challenges in water management caused by anthropogenic impacts as well as climate variability. In addition to this, the scarcity of in situ measurements of soil moisture and groundwater, combined with intrinsic ‘‘scale limitations’’ of traditional methods used in hydrological characterization are further limiting the ability to assess water resource distribution in the region. The primary objective of this study is therefore to apply remotely sensed and model data over Ethiopia in order to (i) test the performance of models and remotely sensed data in modeling water resources distribution in un-gauged arid regions of Ethiopia, (ii) analyze the inter-annual and seasonal variability as well as changes in total water storage (TWS) over Ethiopia, (iii) understand the relationship between TWS changes, rainfall, and soil moisture anomalies over the study region, and (iv) identify the relationship between the characteristics of aquifers and TWS changes. The data used in this study includes; monthly gravity field data from the Gravity Recovery And Climate Experiment (GRACE) mission, rainfall data from the Tropical Rainfall Measuring Mission (TRMM), and soil moisture from the Global Land Data Assimilation System (GLDAS) model. Our investigation covers a period of 8 years from 2003 to 2011.The results of the study show that the western part and the north-eastern lowlands of Ethiopia experienced decrease in TWS water between 2003–2011, whereas all the other regions gained water during the study period. The impact of rainfall seasonality was also seen in the TWS changes. Applying the statistical method of Principal Component Analysis (PCA) to TWS, soil moisture and rainfall variations identified the dominant annual water variability in the western, north-western, northern, and central regions, and the dominant seasonal variability in the western, north-western, and the eastern regions. A correlation analysis between TWS and rainfall indicated a minimum time lag of zero to a maximum of six months, whereas no lag is noticeable between soil moisture anomalies and TWS changes. The delay response and correlation coefficient between rainfall and TWS appears to be related to recharge mechanisms, revealing that most regions of Ethiopia receive indirect recharge. Our results also show that the magnitude of TWS changes is higher in the western region and lower in the north-eastern region, and that the elevation influences soil moisture as well as TWS. 2014 Journal Article http://hdl.handle.net/20.500.11937/19765 10.1016/j.advwatres.2014.07.012 Elsevier fulltext
spellingShingle Ethiopia
Hydrological regimes
GRACE-TWS changes
Climate
TRMM
Awange, Joseph
Gebremichael, M.
Forootan, E.
Wakbulcho, G.
Anyah, R.
Ferreira, V.
Alemayehu, T.
Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets
title Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets
title_full Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets
title_fullStr Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets
title_full_unstemmed Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets
title_short Characterization of Ethiopian mega hydrogeological regimes using GRACE, TRMM and GLDAS Datasets
title_sort characterization of ethiopian mega hydrogeological regimes using grace, trmm and gldas datasets
topic Ethiopia
Hydrological regimes
GRACE-TWS changes
Climate
TRMM
url http://hdl.handle.net/20.500.11937/19765