Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal
High spatio-temporal resolution and accurate long-term rainfall estimates are critical in sustainable water resource planning and management, assessment of climate variability and extremes, and hydro-meteorology-related water system decisions. The recent advent of improved higher-resolution open-acc...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-08-01
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| Series: | Hydrology |
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| Online Access: | https://www.mdpi.com/2306-5338/9/8/146 |
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| author | Surabhi Upadhyay Priya Silwal Rajaram Prajapati Rocky Talchabhadel Sandesh Shrestha Sudeep Duwal Hanik Lakhe |
| author_facet | Surabhi Upadhyay Priya Silwal Rajaram Prajapati Rocky Talchabhadel Sandesh Shrestha Sudeep Duwal Hanik Lakhe |
| author_sort | Surabhi Upadhyay |
| collection | DOAJ |
| description | High spatio-temporal resolution and accurate long-term rainfall estimates are critical in sustainable water resource planning and management, assessment of climate variability and extremes, and hydro-meteorology-related water system decisions. The recent advent of improved higher-resolution open-access satellite-based rainfall products has emerged as a viable complementary to ground-based observations that can often not capture the rainfall variability on a spatial scale. In a developing country such as Nepal, where the rain-gauge monitoring network is sparse and unevenly distributed, satellite rainfall estimates are crucial. However, substantial errors associated with such satellite rainfall estimates pose a challenge to their application, particularly in complex orographic regions such as Nepal. Therefore, these precipitation products must be validated before practical usage to check their accuracy and occurrence consistency. This study aims to assess the reliability of the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) product against ground-based observations from 1986 to 2015 in five medium-sized river basins in Nepal, namely, Babai, Bagmati, Kamala, Kankai, and the West Rapti river basin. A set of continuous evaluation metrics (correlation coefficient, root mean square error, relative bias, and Kling-Gupta efficiency) were used in analyzing the accuracy of CHIRPS and categorical metrics (probability of detection, critical success index, false alarm ratio, and frequency bias index). The Probability of Detection and Critical Success Index values were found to be considerably low (<0.4 on average), while the false alarm ratio was significant (>0.4 on average). It was found that CHIRPS showed better performance in seasonal and monthly time scales with high correlation and indicated greater consistency in non-monsoon seasons. Rainfall amount (less than 10 mm and greater than 150 mm) and rainfall frequency was underestimated by CHIRPS in all basins, while the overestimated rainfall was between 10 and 100 mm in all basins except Kamala. Additionally, CHIRPS overestimated dry days and maximum consecutive dry days in the study area. Our study suggests that CHIRPS rainfall products cannot supplant the ground-based observations but complement rain-gauge networks. However, the reliability of this product in capturing local extreme events (such as floods and droughts) seems less prominent. A high-quality rain gauge network is essential to enhance the accuracy of satellite estimations. |
| first_indexed | 2024-03-09T13:19:19Z |
| format | Article |
| id | doaj.art-4d181d40f27f46118b49750ed6b5ae65 |
| institution | Directory Open Access Journal |
| issn | 2306-5338 |
| language | English |
| last_indexed | 2024-03-09T13:19:19Z |
| publishDate | 2022-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Hydrology |
| spelling | doaj.art-4d181d40f27f46118b49750ed6b5ae652023-11-30T21:31:41ZengMDPI AGHydrology2306-53382022-08-019814610.3390/hydrology9080146Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in NepalSurabhi Upadhyay0Priya Silwal1Rajaram Prajapati2Rocky Talchabhadel3Sandesh Shrestha4Sudeep Duwal5Hanik Lakhe6Smartphones for Water Nepal (S4W-Nepal), Lalitpur 44600, NepalSmartphones for Water Nepal (S4W-Nepal), Lalitpur 44600, NepalSmartphones for Water Nepal (S4W-Nepal), Lalitpur 44600, NepalSmartphones for Water Nepal (S4W-Nepal), Lalitpur 44600, NepalAster Global Environmental Solutions, Inc., North Lawrence, OH 44666, USASmartphones for Water Nepal (S4W-Nepal), Lalitpur 44600, NepalSmartphones for Water Nepal (S4W-Nepal), Lalitpur 44600, NepalHigh spatio-temporal resolution and accurate long-term rainfall estimates are critical in sustainable water resource planning and management, assessment of climate variability and extremes, and hydro-meteorology-related water system decisions. The recent advent of improved higher-resolution open-access satellite-based rainfall products has emerged as a viable complementary to ground-based observations that can often not capture the rainfall variability on a spatial scale. In a developing country such as Nepal, where the rain-gauge monitoring network is sparse and unevenly distributed, satellite rainfall estimates are crucial. However, substantial errors associated with such satellite rainfall estimates pose a challenge to their application, particularly in complex orographic regions such as Nepal. Therefore, these precipitation products must be validated before practical usage to check their accuracy and occurrence consistency. This study aims to assess the reliability of the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) product against ground-based observations from 1986 to 2015 in five medium-sized river basins in Nepal, namely, Babai, Bagmati, Kamala, Kankai, and the West Rapti river basin. A set of continuous evaluation metrics (correlation coefficient, root mean square error, relative bias, and Kling-Gupta efficiency) were used in analyzing the accuracy of CHIRPS and categorical metrics (probability of detection, critical success index, false alarm ratio, and frequency bias index). The Probability of Detection and Critical Success Index values were found to be considerably low (<0.4 on average), while the false alarm ratio was significant (>0.4 on average). It was found that CHIRPS showed better performance in seasonal and monthly time scales with high correlation and indicated greater consistency in non-monsoon seasons. Rainfall amount (less than 10 mm and greater than 150 mm) and rainfall frequency was underestimated by CHIRPS in all basins, while the overestimated rainfall was between 10 and 100 mm in all basins except Kamala. Additionally, CHIRPS overestimated dry days and maximum consecutive dry days in the study area. Our study suggests that CHIRPS rainfall products cannot supplant the ground-based observations but complement rain-gauge networks. However, the reliability of this product in capturing local extreme events (such as floods and droughts) seems less prominent. A high-quality rain gauge network is essential to enhance the accuracy of satellite estimations.https://www.mdpi.com/2306-5338/9/8/146detectionrainfall estimationsatellite productsCHIRPS |
| spellingShingle | Surabhi Upadhyay Priya Silwal Rajaram Prajapati Rocky Talchabhadel Sandesh Shrestha Sudeep Duwal Hanik Lakhe Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal Hydrology detection rainfall estimation satellite products CHIRPS |
| title | Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal |
| title_full | Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal |
| title_fullStr | Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal |
| title_full_unstemmed | Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal |
| title_short | Evaluating Magnitude Agreement and Occurrence Consistency of CHIRPS Product with Ground-Based Observations over Medium-Sized River Basins in Nepal |
| title_sort | evaluating magnitude agreement and occurrence consistency of chirps product with ground based observations over medium sized river basins in nepal |
| topic | detection rainfall estimation satellite products CHIRPS |
| url | https://www.mdpi.com/2306-5338/9/8/146 |
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