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- Ostwald, Madelene, 1966-, et al.
(author)
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Relation between vegetation changes, climate variables and land-use policy in Shaanxi Province, China
- 2007
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In: Geografiska Annaler. Series A, Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 89:4, s. 223-236
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Journal article (peer-reviewed)abstract
- Shaanxi Province in China has been exposed to climate variability and dramatic land-use policies. The aim here is to examine vegetation changes in this area on a regional scale from 2000 to 2004 in relation to land-use changes and climate traits. The data in this assessment include remote sensing information from moderate-resolution imaging spectro-radiometer normalized difference vegetation index from 2000 to 2004, and climate data (precipitation and temperature) from 1956 to 2000. The results show an increase in vegetation production from 2000 to 2004, particularly in the north, which cannot be explained solely by climate impacts. Since the vegetation in the north is more dependent on climate variation than the other parts of Shaanxi due to more serious water limitation, the results suggest that the large-scale land-use policy implemented over the last decade, with a focus on northern Shaanxi, is possibly having an impact on the overall vegetation.
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| 2. |
- Sundborg, A, et al.
(author)
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Water discharges determined from sediment distributions : A palaeohydrological method
- 2001
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In: Geografiska Annaler. Series A, Physical Geography. - 0435-3676 .- 1468-0459. ; 83A:1-2, s. 39-54
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Journal article (peer-reviewed)abstract
- The article presents a simple sediment deposition model, based on current knowledge of the processes of transport and deposition of suspended material. It indicates possibilities of interpreting flow conditions from grain-size distributions at two localities, situated along the water flowline. The model reveals new information an ancient hydrological and sedimentological processes and events. Previously the model has been applied to forecast trap efficiency of reservoirs and predict reservoir sedimentation. In this study the model is used as a palaeohydrological method in studies of annual varves. In varve geochronology a major attention has been paid to varve correlations and valve thickness variations, whereas other sedimentological data have been more or less disregarded. In this article new information on the spatial distribution of particle sizes demonstrate that further knowledge can be gained by careful studies of the patterns of grain-size distributions. Annual variations in water discharges during late glacial time were studied in the Indalsalven and Dalalven valleys in Sweden. Water discharges during the deglaciation seem to have been of the same order of magnitude as in present-day rivers during normal years. During some years catastrophic events occurred, resulting in exceptional water discharges. The magnitudes of these discharges were estimated, and drainage directions were established. It appears from the studies that there are promising prospects of finding out both the magnitude and frequency of processes that until now have been described only in qualitative terms.
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