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| Titel |
Melting of major Glaciers in the western Himalayas: evidence of climatic changes from long term MSU derived tropospheric temperature trend (1979-2008) |
| VerfasserIn |
A. K. Prasad, K.-H. S. Yang, H. M. El-Askary, M. Kafatos |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 12 ; Nr. 27, no. 12 (2009-12-11), S.4505-4519 |
| Datensatznummer |
250016727
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| Publikation (Nr.) |
 copernicus.org/angeo-27-4505-2009.pdf |
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| Zusammenfassung |
| Global warming or the increase of the surface and atmospheric temperatures
of the Earth, is increasingly discernible in the polar, sub-polar and major
land glacial areas. The Himalayan and Tibetan Plateau Glaciers, which are
the largest glaciers outside of the Polar Regions, are showing a large-scale
decrease of snow cover and an extensive glacial retreat. These glaciers such
as Siachen and Gangotri are a major water resource for Asia as they feed
major rivers such as the Indus, Ganga and Brahmaputra. Due to scarcity of
ground measuring stations, the long-term observations of atmospheric
temperatures acquired from the Microwave Sounding Unit (MSU) since 1979–2008
is highly useful. The lower and middle tropospheric temperature trend based
on 30 years of MSU data shows warming of the Northern Hemisphere's
mid-latitude regions. The mean month-to-month warming (up to 0.048±0.026°K/year or 1.44°K
over 30 years) of the mid troposphere (near
surface over the high altitude Himalayas and Tibetan Plateau) is prominent
and statistically significant at a 95% confidence interval. Though the
mean annual warming trend over the Himalayas (0.016±0.005°K/year),
and Tibetan Plateau (0.008±0.006°K/year) is positive, the month to
month warming trend is higher (by 2–3 times, positive and significant) only
over a period of six months (December to May). The factors responsible for
the reversal of this trend from June to November are discussed here. The
inequality in the magnitude of the warming trends of the troposphere between
the western and eastern Himalayas and the IG (Indo-Gangetic) plains is
attributed to the differences in increased aerosol loading (due to dust
storms) over these regions. The monthly mean lower-tropospheric MSU-derived
temperature trend over the IG plains (dust sink region; up to 0.032±0.027°K/year) and dust source regions (Sahara desert, Middle East,
Arabian region, Afghanistan-Iran-Pakistan and Thar Desert regions; up to
0.068±0.033°K/year) also shows a similar pattern of month-to-month
oscillation and six months of enhanced and a statistically significant
warming trend. The enhanced warming trend during the winter and pre-monsoon
months (December–May) may accelerate glacial melt. The unequal distribution
of the warming trend over the year is discussed in this study and is
partially attributed to a number of controlling factors such as sunlight
duration, CO2 trends over the region (2003–2008), water vapor and
aerosol distribution. |
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