Diverging Trends in Rain‐On‐Snow Over High Mountain Asia
Abstract Rain‐on‐snow (ROS) over snow‐dominated regions such as High Mountain Asia (HMA) modulates snowmelt and runoff and is key contributor in influencing water availability and hazards (e.g., floods and landslides). We studied the trends in ROS in HMA over the past two decades from 2001 to 2018 u...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Wiley
2023-03-01
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| Series: | Earth's Future |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2022EF003009 |
| _version_ | 1827586246471319552 |
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| author | Fadji Z. Maina Sujay V. Kumar |
| author_facet | Fadji Z. Maina Sujay V. Kumar |
| author_sort | Fadji Z. Maina |
| collection | DOAJ |
| description | Abstract Rain‐on‐snow (ROS) over snow‐dominated regions such as High Mountain Asia (HMA) modulates snowmelt and runoff and is key contributor in influencing water availability and hazards (e.g., floods and landslides). We studied the trends in ROS in HMA over the past two decades from 2001 to 2018 using the land surface model Noah‐MP driven by an ensemble precipitation data set. Our results show that changes in precipitation phase and rainfall are altering ROS. Because of the strong physical heterogeneity and atmospheric dynamics of HMA, ROS characteristics and trends are region‐dependent and ROS occurs predominantly over the Indus, Ganges‐Brahmaputra, and northwestern basins. In the Indus, ROS representing ∼5% of the annual precipitation and ∼20% of the annual snowmelt, has an increasing trend. This is contrary to the Ganges‐Brahmaputra characterized by decreasing ROS trends, where it represents ∼11% of the annual precipitation and ∼60% of the annual snowmelt. In the northwestern basins, ROS has bidirectional trends due to elevation patterns and trends in rainfall, and it constitutes ∼5 to ∼10% of the annual precipitation. Increasing trends in ROS over Indus contribute to reducing the snowpack in late summer, with concerns of reduced water availability and increased groundwater exploitation. Similarly, because of its high amount and contribution to snowmelt, the decreasing ROS trends in the Ganges‐Brahmaputra will have consequences of decreased recharge from the headwaters and exacerbated use of groundwater unless increasing trends in rainfall compensate for the decreasing snowmelt. These results provide new insights on ROS‐driven changes in the hydrological cycle over HMA. |
| first_indexed | 2024-03-08T23:58:58Z |
| format | Article |
| id | doaj.art-a2656936541e4159898bedbd7feb4f8f |
| institution | Directory Open Access Journal |
| issn | 2328-4277 |
| language | English |
| last_indexed | 2024-03-08T23:58:58Z |
| publishDate | 2023-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Earth's Future |
| spelling | doaj.art-a2656936541e4159898bedbd7feb4f8f2023-12-12T22:51:52ZengWileyEarth's Future2328-42772023-03-01113n/an/a10.1029/2022EF003009Diverging Trends in Rain‐On‐Snow Over High Mountain AsiaFadji Z. Maina0Sujay V. Kumar1Hydrological Sciences Laboratory NASA Goddard Space Flight Center Greenbelt MD USAHydrological Sciences Laboratory NASA Goddard Space Flight Center Greenbelt MD USAAbstract Rain‐on‐snow (ROS) over snow‐dominated regions such as High Mountain Asia (HMA) modulates snowmelt and runoff and is key contributor in influencing water availability and hazards (e.g., floods and landslides). We studied the trends in ROS in HMA over the past two decades from 2001 to 2018 using the land surface model Noah‐MP driven by an ensemble precipitation data set. Our results show that changes in precipitation phase and rainfall are altering ROS. Because of the strong physical heterogeneity and atmospheric dynamics of HMA, ROS characteristics and trends are region‐dependent and ROS occurs predominantly over the Indus, Ganges‐Brahmaputra, and northwestern basins. In the Indus, ROS representing ∼5% of the annual precipitation and ∼20% of the annual snowmelt, has an increasing trend. This is contrary to the Ganges‐Brahmaputra characterized by decreasing ROS trends, where it represents ∼11% of the annual precipitation and ∼60% of the annual snowmelt. In the northwestern basins, ROS has bidirectional trends due to elevation patterns and trends in rainfall, and it constitutes ∼5 to ∼10% of the annual precipitation. Increasing trends in ROS over Indus contribute to reducing the snowpack in late summer, with concerns of reduced water availability and increased groundwater exploitation. Similarly, because of its high amount and contribution to snowmelt, the decreasing ROS trends in the Ganges‐Brahmaputra will have consequences of decreased recharge from the headwaters and exacerbated use of groundwater unless increasing trends in rainfall compensate for the decreasing snowmelt. These results provide new insights on ROS‐driven changes in the hydrological cycle over HMA.https://doi.org/10.1029/2022EF003009rain‐on‐snowHigh Mountain Asiasnow dynamicssnowmeltrunoffwarming |
| spellingShingle | Fadji Z. Maina Sujay V. Kumar Diverging Trends in Rain‐On‐Snow Over High Mountain Asia Earth's Future rain‐on‐snow High Mountain Asia snow dynamics snowmelt runoff warming |
| title | Diverging Trends in Rain‐On‐Snow Over High Mountain Asia |
| title_full | Diverging Trends in Rain‐On‐Snow Over High Mountain Asia |
| title_fullStr | Diverging Trends in Rain‐On‐Snow Over High Mountain Asia |
| title_full_unstemmed | Diverging Trends in Rain‐On‐Snow Over High Mountain Asia |
| title_short | Diverging Trends in Rain‐On‐Snow Over High Mountain Asia |
| title_sort | diverging trends in rain on snow over high mountain asia |
| topic | rain‐on‐snow High Mountain Asia snow dynamics snowmelt runoff warming |
| url | https://doi.org/10.1029/2022EF003009 |
| work_keys_str_mv | AT fadjizmaina divergingtrendsinrainonsnowoverhighmountainasia AT sujayvkumar divergingtrendsinrainonsnowoverhighmountainasia |