Near real-time measurements of snow water equivalent in the Nepal Himalayas
| Autor: | James D. Kirkham, Inka Koch, Tuomo M. Saloranta, Maxime Litt, Emmy E. Stigter, Knut Møen, Amrit Thapa, Kjetil Melvold, Walter W. Immerzeel |
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| Přispěvatelé: | Kirkham, James [0000-0002-0506-1625], Apollo - University of Cambridge Repository |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
010504 meteorology & atmospheric sciences
Real-time computing Himalaya gamma radiation Elevation Effects of high altitude on humans Snowpack snow 010502 geochemistry & geophysics Water equivalent Snow 01 natural sciences 13. Climate action snow water equivalent high altitude near real time General Earth and Planetary Sciences Environmental science lcsh:Q Precipitation Water cycle Meltwater lcsh:Science 0105 earth and related environmental sciences |
| Zdroj: | Frontiers in Earth Science, Cryosphere, 7. Frontiers Media Frontiers in Earth Science, Vol 7 (2019) |
| Popis: | Seasonal snow is an important component of the Himalayan hydrological system, but a lack of observations at high altitude hampers understanding and forecasting of water availability in this region. Here, we use a passive gamma ray sensor that measures snow water equivalent (SWE) and complementary meteorological instruments installed at 4962 m a.s.l. in the Nepal Himalayas to quantify the evolution of SWE and snow depth over a 2-year period. We assess the accuracy, spatial representativeness and the applicability of the SWE and snow depth measurements using time-lapse camera imagery and field observations. The instrument setup performs well for snowpacks >50 mm SWE, but caution must be applied when interpreting measurements from discontinuous, patchy snow cover or those that contain lenses of refrozen meltwater. Over their typical ∼6-month lifetime, snowpacks in this setting can attain up to 200 mm SWE, of which 10–15% consists of mixed precipitation and rain-on-snow events. Precipitation gauges significantly underrepresent the solid fraction of precipitation received at this elevation by almost 40% compared to the gamma ray sensor. The application of sub-daily time-lapse camera imagery can help to correctly interpret and increase the reliability and representativeness of snowfall measurements. Our monitoring approach provides high quality, continuous, near-real time information that is essential to develop snow models in this data scarce region. We recommend that a similar instrument setup be extended into remote Himalayan environments to facilitate widespread snowpack monitoring and further our understanding of the high-altitude water cycle. |
| Databáze: | OpenAIRE |
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