Deriving Snow Cover Metrics for Alaska from MODIS
Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products provide an opportunity for determining snow onset and melt dates across broad geographic regions; however, cloud cover and polar darkness are limiting factors at higher latitudes. This study presents snow onset and melt...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2015-09-01
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| Series: | Remote Sensing |
| Subjects: | |
| Online Access: | http://www.mdpi.com/2072-4292/7/10/12961 |
| _version_ | 1828143593258221568 |
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| author | Chuck Lindsay Jiang Zhu Amy E. Miller Peter Kirchner Tammy L. Wilson |
| author_facet | Chuck Lindsay Jiang Zhu Amy E. Miller Peter Kirchner Tammy L. Wilson |
| author_sort | Chuck Lindsay |
| collection | DOAJ |
| description | Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products provide an opportunity for determining snow onset and melt dates across broad geographic regions; however, cloud cover and polar darkness are limiting factors at higher latitudes. This study presents snow onset and melt dates for Alaska, portions of western Canada and the Russian Far East derived from Terra MODIS snow cover daily 500 m grid data (MOD10A1) and evaluates our method for filling data gaps caused by clouds or polar darkness. Pixels classified as cloud or no data were reclassified by: spatial filtering using neighboring pixel values; temporal filtering using pixel values for days before/after cloud cover; and snow-cycle filtering based on a time series assessment of a pixel’s position within snow accumulation, cover or melt periods. During the 2012 snow year, these gap-filling methods reduced cloud pixels from 27.7% to 3.1%. A total of 12 metrics (e.g., date of first and last snow, date of persistent snow cover and periods of intermittence) for each pixel were calculated by snow year. A comparison of MODIS-derived snow onset and melt dates with in situ observations from 244 weather stations generally showed an early bias in MODIS-derived dates and an effect of increasing cloudiness exacerbating bias. Our results show that mean regional duration of seasonal snow cover is 179–311 days/year and that snow cover is often intermittent, with 41% of the area experiencing ≥2 snow-covered periods during a snow season. Other regional-scale patterns in the timing of snow onset and melt are evident in the yearly 500 m gridded products publically available at http://static.gina.alaska.edu/NPS_products/MODIS_snow/. |
| first_indexed | 2024-04-11T19:59:46Z |
| format | Article |
| id | doaj.art-03927d91b2304002882c9ffe51a5db69 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-04-11T19:59:46Z |
| publishDate | 2015-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-03927d91b2304002882c9ffe51a5db692022-12-22T04:05:39ZengMDPI AGRemote Sensing2072-42922015-09-01710129611298510.3390/rs71012961rs71012961Deriving Snow Cover Metrics for Alaska from MODISChuck Lindsay0Jiang Zhu1Amy E. Miller2Peter Kirchner3Tammy L. Wilson4Southwest Alaska Network Inventory and Monitoring Program, National Park Service, 240 W 5th Ave., Anchorage, AK 99501, USAGeographic Information Network of Alaska, University of Alaska Fairbanks, Box 75-7275 GINA WRRB 111, 909 Koyukuk Dr., Fairbanks, AK 99775, USASouthwest Alaska Network Inventory and Monitoring Program, National Park Service, 240 W 5th Ave., Anchorage, AK 99501, USASouthwest Alaska Network Inventory and Monitoring Program, National Park Service, 240 W 5th Ave., Anchorage, AK 99501, USASouthwest Alaska Network Inventory and Monitoring Program, National Park Service, 240 W 5th Ave., Anchorage, AK 99501, USAModerate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products provide an opportunity for determining snow onset and melt dates across broad geographic regions; however, cloud cover and polar darkness are limiting factors at higher latitudes. This study presents snow onset and melt dates for Alaska, portions of western Canada and the Russian Far East derived from Terra MODIS snow cover daily 500 m grid data (MOD10A1) and evaluates our method for filling data gaps caused by clouds or polar darkness. Pixels classified as cloud or no data were reclassified by: spatial filtering using neighboring pixel values; temporal filtering using pixel values for days before/after cloud cover; and snow-cycle filtering based on a time series assessment of a pixel’s position within snow accumulation, cover or melt periods. During the 2012 snow year, these gap-filling methods reduced cloud pixels from 27.7% to 3.1%. A total of 12 metrics (e.g., date of first and last snow, date of persistent snow cover and periods of intermittence) for each pixel were calculated by snow year. A comparison of MODIS-derived snow onset and melt dates with in situ observations from 244 weather stations generally showed an early bias in MODIS-derived dates and an effect of increasing cloudiness exacerbating bias. Our results show that mean regional duration of seasonal snow cover is 179–311 days/year and that snow cover is often intermittent, with 41% of the area experiencing ≥2 snow-covered periods during a snow season. Other regional-scale patterns in the timing of snow onset and melt are evident in the yearly 500 m gridded products publically available at http://static.gina.alaska.edu/NPS_products/MODIS_snow/.http://www.mdpi.com/2072-4292/7/10/12961MODISMOD10A1snow coverAlaskacloud filteringgap fillingsnow cover durationsnow onsetsnow melt |
| spellingShingle | Chuck Lindsay Jiang Zhu Amy E. Miller Peter Kirchner Tammy L. Wilson Deriving Snow Cover Metrics for Alaska from MODIS Remote Sensing MODIS MOD10A1 snow cover Alaska cloud filtering gap filling snow cover duration snow onset snow melt |
| title | Deriving Snow Cover Metrics for Alaska from MODIS |
| title_full | Deriving Snow Cover Metrics for Alaska from MODIS |
| title_fullStr | Deriving Snow Cover Metrics for Alaska from MODIS |
| title_full_unstemmed | Deriving Snow Cover Metrics for Alaska from MODIS |
| title_short | Deriving Snow Cover Metrics for Alaska from MODIS |
| title_sort | deriving snow cover metrics for alaska from modis |
| topic | MODIS MOD10A1 snow cover Alaska cloud filtering gap filling snow cover duration snow onset snow melt |
| url | http://www.mdpi.com/2072-4292/7/10/12961 |
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