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Defining phenology events with digital repeat photography

Jonsson, Johannes LU (2012) In Student thesis series INES NGEK01 20121
Dept of Physical Geography and Ecosystem Science
Abstract
Phenology is the study of the timing of natural events such as leaf-out, bud burst and senescence relative to climate change. It is important to understand how the climate change will affect the timing of these events as it in turn affects the carbon-, nutrient- and the hydrological cycles. Field observations is the most common way to gather phenology data but the result is dependent on the skill of the observer and is very time consuming. Remote sensing has under the last decades been used more in phenology studies. However the low spatial and temporal resolution from satellite photos makes it hard to study local phenology. Therefore new methods have emerged to complement this. Digital repeat photography is a method which uses regular... (More)
Phenology is the study of the timing of natural events such as leaf-out, bud burst and senescence relative to climate change. It is important to understand how the climate change will affect the timing of these events as it in turn affects the carbon-, nutrient- and the hydrological cycles. Field observations is the most common way to gather phenology data but the result is dependent on the skill of the observer and is very time consuming. Remote sensing has under the last decades been used more in phenology studies. However the low spatial and temporal resolution from satellite photos makes it hard to study local phenology. Therefore new methods have emerged to complement this. Digital repeat photography is a method which uses regular digital cameras mounted to capture the same area over a longer time period. The captured red, green and blue color values in the photographs can then be used to calculate the appearance of certain phenology events. This study provides a method how to quantitatively define the start and end of the growing season which can be used to indicate climate change. Phenology phases for four different mountain birch stands including canopy and understory in Abisko, Sweden, were studied using data from 2011. The calculated start of the growing season varied with two days between the different stands and follows the field observed phenology. The calculated color values from the photographs had a peak when all leaves were fully developed. The end of the growing season varied by six days between all birch stands. The senescence period was harder to define than the leaf-out event as it includes both the decrease from the colorization of leaves and when leaves fall to the ground. (Less)
Abstract (Swedish)
Populärvetenskaplig sammanfattning
Fenologi innebär studier av naturligt återkommande händelser som till exempel bladsprickning, knoppbristning och vissningen av blad. Det är viktigt att förstå hur klimatförändringen påverkar tidpunkten då dessa händelser sker eftersom det i sin tur påverkar kol-, närings- och den hydrologiska cykeln. Fältobservationer har varit den mest använda metoden för att samla in fenologiskdata men resultatet beror på observatörens färdighet och är mycket tidskrävande. Fjärranalys har under det senaste årtiondet blivit mer användbart i fenologistudier. Den låga spatiala och temporala kvaliteten av fjärranalysdata från satelliter har medförit att nya metoder utvecklats för att komplementera detta. Upprepad digital... (More)
Populärvetenskaplig sammanfattning
Fenologi innebär studier av naturligt återkommande händelser som till exempel bladsprickning, knoppbristning och vissningen av blad. Det är viktigt att förstå hur klimatförändringen påverkar tidpunkten då dessa händelser sker eftersom det i sin tur påverkar kol-, närings- och den hydrologiska cykeln. Fältobservationer har varit den mest använda metoden för att samla in fenologiskdata men resultatet beror på observatörens färdighet och är mycket tidskrävande. Fjärranalys har under det senaste årtiondet blivit mer användbart i fenologistudier. Den låga spatiala och temporala kvaliteten av fjärranalysdata från satelliter har medförit att nya metoder utvecklats för att komplementera detta. Upprepad digital fotografering är en metod som använder vanliga digitalkameror monterade för att fotografera samma område under långa tidsperioder. De registrerade färgvärdena från fotografiernas röda, gröna och blå kanaler kan sedan användas för att definiera fenologiska händelser. Denna studie tillhandahåller en metod för att kvantitativt bestämma start och slut på växtsäsongen som kan användas för att indikera att klimatet förändras. Fenologiska händelser hos fyra olika fjällbjörkstånd samt krontak och björkens undre parti i Abisko, Sverige, har studerats för år 2011. Den beräknade starten av växtsäsongen varierade med två dagar mellan björkbestånden och följer fenologin som observerats i fält. De beräknade färgvärdena nådde sitt maximum när bladen var fullt utvecklade. Slutet på växtsäsongen växlade med sex dagar mellan de olika björkbestånden. Vissningsperioden var svårare att definiera än bladsprickningen då vissningen innehåller två händelser som sänker färgvärdena i bilderna: färgförändring av bladen samt lövfällning (Less)
Please use this url to cite or link to this publication:
author
Jonsson, Johannes LU
supervisor
organization
alternative title
Definiering av fenologiska händelser med digital repeat photography
course
NGEK01 20121
year
type
M2 - Bachelor Degree
subject
keywords
geography, physical geography, digital repeat photography, phenology, mountain birch, geografi, naturgeografi, fenologi, fjällbjörk
publication/series
Student thesis series INES
report number
250
language
English
id
2797262
date added to LUP
2012-09-19 17:37:53
date last changed
2012-09-19 17:37:53
@misc{2797262,
  abstract     = {Phenology is the study of the timing of natural events such as leaf-out, bud burst and senescence relative to climate change. It is important to understand how the climate change will affect the timing of these events as it in turn affects the carbon-, nutrient- and the hydrological cycles. Field observations is the most common way to gather phenology data but the result is dependent on the skill of the observer and is very time consuming. Remote sensing has under the last decades been used more in phenology studies. However the low spatial and temporal resolution from satellite photos makes it hard to study local phenology. Therefore new methods have emerged to complement this. Digital repeat photography is a method which uses regular digital cameras mounted to capture the same area over a longer time period. The captured red, green and blue color values in the photographs can then be used to calculate the appearance of certain phenology events. This study provides a method how to quantitatively define the start and end of the growing season which can be used to indicate climate change. Phenology phases for four different mountain birch stands including canopy and understory in Abisko, Sweden, were studied using data from 2011. The calculated start of the growing season varied with two days between the different stands and follows the field observed phenology. The calculated color values from the photographs had a peak when all leaves were fully developed. The end of the growing season varied by six days between all birch stands. The senescence period was harder to define than the leaf-out event as it includes both the decrease from the colorization of leaves and when leaves fall to the ground.},
  author       = {Jonsson, Johannes},
  keyword      = {geography,physical geography,digital repeat photography,phenology,mountain birch,geografi,naturgeografi,fenologi,fjällbjörk},
  language     = {eng},
  note         = {Student Paper},
  series       = {Student thesis series INES},
  title        = {Defining phenology events with digital repeat photography},
  year         = {2012},
}