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Analysis of NOAA-AVHRR time series to investigate climate induced changes of vegetation in the Alps and surrounding landscapes

English title Analysis of NOAA-AVHRR time series to investigate climate induced changes of vegetation in the Alps and surrounding landscapes
Applicant Wunderle Stefan
Number 111894
Funding scheme Project funding (Div. I-III)
Research institution Geographisches Institut Universität Bern
Institution of higher education University of Berne - BE
Main discipline Other disciplines of Environmental Sciences
Start/End 01.04.2006 - 31.03.2009
Approved amount 161'655.00
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Keywords (7)

vegetation dynamics; start of season; european alps; NOAA_AVHRR; normalized difference vegetation index; time series analysis; NOAA-AVHRR

Lay Summary (English)

Lead
Lay summary
Without doubt the climate of the Alps has changed during the last decades, which result in a shift of vegetation zones, a new composition of species and most important the duration of the vegetation period. A trend analysis based on data of the Swiss phenological network showed an earlier flowering, bud burst and leaf unfolding in the year, whereas coloring of the leaves occurs later. This trend is not uniform throughout the Alps and exhibits strong regional distinction with a clear north-south difference and a contrast between lowlands and altitudes above 1000m. Although, some sites of the phenological network exist, their spatial distribution in the Alps is sparse. Furthermore, only a few measurement sites exist to monitor the actual vegetation dynamics in the Alps. In most investigations monitoring lasts only some years and only a few sites were observed for more than 10 years. Knowledge about the influence of climate on the spatial variations of vegetation dynamics is needed in order to assess future changes of vegetation due to climate change.Therefore, the proposed project focuses on the derivation of vegetation dynamics (start of season, maximum, end of season, duration of vegetationactivity) and their variability in a changing climate and aims at addressing the following scientific questions:a)Does the sensitivity to warming differ across key components of landcover?b)Is there a clear difference between North-South and East-West Alps andelevation zones?c)How strong is the temperature signal in comparison to “chillingduration” and “photoperiod”?A homogenous and consistent data set with a high spatial (1.1km2) and temporal (1day) resolution based on data of the Advanced Very High Resolution Radiometer (AVHRR) on board of the NOAA-satellites will be generated. The Normalized Difference Vegetation Index (NDVI), a measure for the vegetation activity, will be derived for the years 1987 until 2006 using processing software developed to take into account the special conditions (topography, cloud coverage) of the Alps. The NDVI data set will be used to derive the annual vegetation dynamics with a spatial resolution of 1day (depending on the cloud coverage) and for each pixel.Thus, for the first time vegetated areas in all altitudinal zones and regions of the Alps will be analyzed on their variability of vegetation dynamics. These results are the starting point to identify the most important patterns of vegetation dynamic (start of season, maximum value, duration of maximum values, end of season, duration of season) and climate year-to-year variability. Temperature and precipitation will be taken into account to explain the dependence of vegetation variability on climate.The outcome of the vegetation variability will be compared with the variability of spring onset as obtained from phenological observation networks in order to find out whether phenological observations are representative for a region.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
132172 Albedo time series of the European Alps based on NOAA AVHRR data (1985 - 2012) 01.02.2012 Project funding (Div. I-III)
132172 Albedo time series of the European Alps based on NOAA AVHRR data (1985 - 2012) 01.02.2012 Project funding (Div. I-III)

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