scholarly journals The importance of glacier and forest change in hydrological climate-impact studies

2013 ◽  
Vol 17 (2) ◽  
pp. 619-635 ◽  
Author(s):  
N. Köplin ◽  
B. Schädler ◽  
D. Viviroli ◽  
R. Weingartner
Keyword(s):  
Land Cover ◽  
Water Balance ◽  
Catchment Area ◽  
Forest Cover ◽  
Control Period ◽  
Climate Impact ◽  
Glacier Retreat ◽  
Climate Scenarios ◽  
Forest Change ◽  
Impact Studies

Abstract. Changes in land cover alter the water balance components of a catchment, due to strong interactions between soils, vegetation and the atmosphere. Therefore, hydrological climate impact studies should also integrate scenarios of associated land cover change. To reflect two severe climate-induced changes in land cover, we applied scenarios of glacier retreat and forest cover increase that were derived from the temperature signals of the climate scenarios used in this study. The climate scenarios were derived from ten regional climate models from the ENSEMBLES project. Their respective temperature and precipitation changes between the scenario period (2074–2095) and the control period (1984–2005) were used to run a hydrological model. The relative importance of each of the three types of scenarios (climate, glacier, forest) was assessed through an analysis of variance (ANOVA). Altogether, 15 mountainous catchments in Switzerland were analysed, exhibiting different degrees of glaciation during the control period (0–51%) and different degrees of forest cover increase under scenarios of change (12–55% of the catchment area). The results show that even an extreme change in forest cover is negligible with respect to changes in runoff, but it is crucial as soon as changes in evaporation or soil moisture are concerned. For the latter two variables, the relative impact of forest change is proportional to the magnitude of its change. For changes that concern 35% of the catchment area or more, the effect of forest change on summer evapotranspiration is equally or even more important than the climate signal. For catchments with a glaciation of 10% or more in the control period, the glacier retreat significantly determines summer and annual runoff. The most important source of uncertainty in this study, though, is the climate scenario and it is highly recommended to apply an ensemble of climate scenarios in the impact studies. The results presented here are valid for the climatic region they were tested for, i.e., a humid, mid-latitude mountainous environment. They might be different for regions where the evaporation is a major component of the water balance, for example. Nevertheless, a hydrological climate-impact study that assesses the additional impacts of forest and glacier change is new so far and provides insight into the question whether or not it is necessary to account for land cover changes as part of climate change impacts on hydrological systems.

scholarly journals The importance of glacier and forest change in hydrological climate-impact studies

2012 ◽  
Vol 9 (5) ◽  
pp. 5983-6021 ◽  
Author(s):  
N. Köplin ◽  
B. Schädler ◽  
D. Viviroli ◽  
R. Weingartner
Keyword(s):  
Land Cover ◽  
Water Balance ◽  
Catchment Area ◽  
Forest Cover ◽  
Control Period ◽  
Climate Impact ◽  
Glacier Retreat ◽  
Climate Scenarios ◽  
Forest Change ◽  
Impact Studies

Abstract. Changes in land cover alter the water balance components of a catchment, due to strong interactions between soils, vegetation and the atmosphere. Therefore, hydrological climate impact studies should also integrate scenarios of associated land cover change. To reflect two severe climate-induced changes in land cover, we applied scenarios of glacier retreat and forest cover increase that were derived from the temperature signals of the climate scenarios used in this study. The climate scenarios consist of ten regional climate models from the ENSEMBLES project; their respective temperature and precipitation deltas are used to run a hydrological model. The relative importance of each of the three types of scenarios (climate, glacier, forest) is assessed through an analysis of variance (ANOVA). Altogether, 15 mountainous catchments in Switzerland are analysed, exhibiting different degrees of glaciation during the control period (0–51%) and different degrees of forest cover increase under scenarios of change (12–55% of the catchment area). The results show that even an extreme change in forest cover is negligible with respect to changes in runoff, but it is crucial as soon as evaporation or soil moisture is concerned. For the latter two variables, the relative impact of forest change is proportional to the magnitude of its change. For changes that concern 35% of the catchment area or more, the effect of forest change on summer evapotranspiration is equally or even more important than the climate signal. For catchment with a glaciation of 10% or more in the control period, the glacier retreat significantly determines summer and annual runoff. The most important source of uncertainty in hydrological climate impact studies is the climate scenario, though, and it is highly recommended to apply an ensemble of climate scenarios in impact studies. The results presented here are valid for the climatic region they were tested for, i.e. a humid, mid-latitude mountainous environment. They might be different for regions where the evaporation is a major component of the water balance, for example. Nevertheless, a hydrological climate-impact study that assesses the additional impacts of forest and glacier change is new so far and provides insight into the question whether or not it is necessary to account for land cover changes as part of climate change impacts on hydrological systems.

scholarly journals Assessment of Large Scale Land Cover Change Classifications and Drivers of Deforestation in Indonesia

2015 ◽  
Vol XL-7/W3 ◽  
pp. 557-562 ◽  
Author(s):  
A. Wijaya ◽  
R. A. Sugardiman Budiharto ◽  
A. Tosiani ◽  
D. Murdiyarso ◽  
L.V. Verchot
Keyword(s):  
Land Cover ◽  
Large Scale ◽  
Forest Cover ◽  
Spatial Information ◽  
Brazilian Amazon ◽  
Congo Basin ◽  
Reliable Estimate ◽  
Forest Conversion ◽  
Forest Cover Change ◽  
Forest Change

Indonesia possesses the third largest tropical forests coverage following Brazilian Amazon and Congo Basin regions. This country, however, suffered from the highest deforestation rate surpassing deforestation in the Brazilian Amazon in 2012. National capacity for forest change assessment and monitoring has been well-established in Indonesia and the availability of national forest inventory data could largely assist the country to report their forest carbon stocks and change over more than two decades. This work focuses for refining forest cover change mapping and deforestation estimate at national scale applying over 10,000 scenes of Landsat scenes, acquired in 1990, 1996, 2000, 2003, 2006, 2009, 2011 and 2012. Pre-processing of the data includes, geometric corrections and image mosaicking. The classification of mosaic Landsat data used multi-stage visual observation approaches, verified using ground observations and comparison with other published materials. There are 23 land cover classes identified from land cover data, presenting spatial information of forests, agriculture, plantations, non-vegetated lands and other land use categories. We estimated the magnitude of forest cover change and assessed drivers of forest cover change over time. Forest change trajectories analysis was also conducted to observe dynamics of forest cover across time. This study found that careful interpretations of satellite data can provide reliable information on forest cover and change. Deforestation trend in Indonesia was lower in 2000-2012 compared to 1990-2000 periods. We also found that over 50% of forests loss in 1990 remains unproductive in 2012. Major drivers of forest conversion in Indonesia range from shrubs/open land, subsistence agriculture, oil palm expansion, plantation forest and mining. The results were compared with other available datasets and we obtained that the MOF data yields reliable estimate of deforestation.

scholarly journals Using Geospatial Analysis to Map Forest Change in New Hampshire: 1996–Present

2020 ◽  
Vol 118 (6) ◽  
pp. 598-612
Author(s):  
Heather Grybas ◽  
Russell G Congalton ◽  
Andrew F Howard
Keyword(s):  
Land Cover ◽  
New Hampshire ◽  
Forest Cover ◽  
Landsat Imagery ◽  
The State ◽  
Forest Cover Change ◽  
Forest Change ◽  
Change Analysis ◽  
Land Cover Map ◽  
Forest Use

Abstract New Hampshire’s forests are vitally important to the state’s economy; however, there are indications that the state is experiencing a continuous loss in forest cover. We sought to investigate forest cover trends in New Hampshire. A baseline trend in forest cover between 1996 and 2010 was established using National Oceanic and Atmospheric Administration Coastal Change Analysis Program land cover data. A land cover map was then generated from Landsat imagery to extend the baseline trend to 2018. Results show that the state has experienced a continual decline in forest cover with the annual net loss steadily increasing from 0.14% between 1996 and 2001 to 0.27% between 2010 and 2018. Additionally, the more urbanized counties in southern New Hampshire are experiencing some of the greatest rates of net forest loss, most likely because of urbanization and agricultural expansion. This study demonstrated an effective methodology for tracking forest cover change and will hopefully inform future forest use policies.

scholarly journals Effect of deforestation on watershed water balance: hydrological modelling-based approach / Vplyv odlesnenia na vodnú bilanciu povodia: prístup na báze hydrologického modelovania

2015 ◽  
Vol 61 (2) ◽  
pp. 89-100 ◽  
Author(s):  
Tomáš Hlásny ◽  
Dušan Kočický ◽  
Martin Maretta ◽  
Zuzana Sitková ◽  
Ivan Barka ◽  
...  
Keyword(s):  
Land Cover ◽  
Water Balance ◽  
Surface Runoff ◽  
Forest Cover ◽  
Base Flow ◽  
Peak Discharge ◽  
Precipitation Event ◽  
Total Precipitation ◽  
Watershed Hydrology ◽  
Water Balance Components

Abstract Changes in land cover, including deforestation, can have significant effect on watershed hydrology. We used hydrological model with distributed parameters to evaluate the effect of simulated deforestation on water balance components in the watershed Ulička (97 km2, 84.3% forest cover) located in the eastern Slovakia. Under the current land cover, average interception accounted for 21.1% of the total precipitation during the calibration period 2001-2013. Most of the precipitation (77%) infiltrated into the soil profile, and less than half of this amount percolated into the ground water aquifer. The surface runoff accounted for 1.2% of the total precipitation only, while the interflow accounted for ca. 12%. The largest proportion of the precipitation contributed to the base flow (23%). Watershed`s deforestation induced significant decrease in the interception and evapotranspiration (by 76% and 12%, respectively). At the same time, total runoff, surface runoff, interflow and base flow increased by 20.4, 38.8, 9.0 and 25.5%, respectively. Daily discharge increased by 20%. The deforestation significantly increased peak discharge induced by a simulated extreme precipitation event with the recurrence interval of 100 years. In the deforested watershed, the peak discharge was higher by 58% as compared with the current land cover. Peak discharge occurred in 432 minutes with the current land cover and in 378 minutes with deforestation, after the precipitation event had started. The presented assessment emphasized the risk of adverse effect of excessive deforestation on watershed hydrology. At the same time, the developed model allows testing the effect of other land cover scenarios, and thus supports management in the investigated watershed.

Modelling and statistical analysis of catchment water balance and discharge in Finland in 1951–2099 using transient climate scenarios

2012 ◽  
Vol 3 (1) ◽  
pp. 55-78 ◽  
Author(s):  
Noora Veijalainen ◽  
Johanna Korhonen ◽  
Bertel Vehviläinen ◽  
Harri Koivusalo
Keyword(s):  
Water Balance ◽  
Bias Correction ◽  
Climate Models ◽  
Hydrological Model ◽  
Control Period ◽  
Mapping Method ◽  
Climate Modelling ◽  
Climate Scenarios ◽  
Water Balance Components ◽  
Low Flows

In this study climate change impacts on water balance components were estimated from transient climate scenarios for 1951–2099 in Finland. The future changes in evapotranspiration and discharge in annual and seasonal scales as well as annual mean high and low flows were projected for four catchments in different parts of Finland. The assessment was carried out using temperature and precipitation series simulated by four regional climate models (RCMs) as input to a conceptual hydrological model. The daily data from RCMs was bias corrected with the quantile–quantile mapping method and statistical properties of the simulated discharges were analysed to detect trends over time. Without bias correction the simulated discharges in the control period did not match the observed discharges, but the fit was improved considerably after bias correction. The results showed that seasonal changes, most importantly increase in winter runoff, were clearly visible and consistent in different climate scenarios and catchments. Individual scenarios also produced changes in annual mean, high and low flows, but without consistency in scenarios. The use of bias corrected RCM data as input to the hydrological model enables transient simulations, but the simulation results aggregate considerable uncertainties from the climate modelling, bias correction and the hydrological model.

scholarly journals SPATIOTEMPORAL CHANGE DETECTION IN FOREST COVER DYNAMICS ALONG LANDSLIDE SUSCEPTIBLE REGION OF KARAKORAM HIGHWAY, PAKISTAN

2018 ◽  
Vol IV-3 ◽  
pp. 177-184
Author(s):  
Barira Rashid ◽  
Javed Iqbal
Keyword(s):  
Land Cover ◽  
Urban Areas ◽  
Forest Cover ◽  
Accuracy Assessment ◽  
Forest Degradation ◽  
Native Forest ◽  
Landsat 8 ◽  
Forest Cover Change ◽  
Forest Change ◽  
Karakoram Highway

Forest Cover dynamics and its understanding is essential for a country’s social, environmental, and political engagements. This research provides a methodical approach for the assessment of forest cover along Karakoram Highway. It has great ecological and economic significance because it’s a part of China-Pakistan Economic Corridor. Landsat 4, 5 TM, Landsat 7 ETM and Landsat 8 OLI imagery for the years 1990, 2000, 2010 and 2016 respectively were subjected to supervised classification in ArcMap 10.5 to identify forest change. The study area was categorized into five major land use land cover classes i.e., Forest, vegetation, urban, open land and snow cover. Results from post classification forest cover change maps illustrated notable decrease of almost 26 % forest cover over the time period of 26 years. The accuracy assessment revealed the kappa coefficients 083, 0.78, 0.77 and 0.85, respectively. Major reason for this change is an observed replacement of native forest cover with urban areas (12.5 %) and vegetation (18.6 %) However, there is no significant change in the reserved forests along the study area that contributes only 2.97 % of the total forest cover. The extensive forest degradation and risk prone topography of the region has increased the environmental risk of landslides. Hence, effective policies and forest management is needed to protect not only the environmental and aesthetic benefits of the forest cover but also to manage the disaster risks. Apart from the forest assessment, this research gives an insight of land cover dynamics, along with causes and consequences, thereby showing the forest degradation hotspots.

scholarly journals Relationships between burned area, forest cover loss, and land cover change in the Brazilian Amazon based on satellite data

2015 ◽  
Vol 12 (20) ◽  
pp. 6033-6043 ◽  
Author(s):  
T. Fanin ◽  
G. R. van der Werf
Keyword(s):  
Land Cover ◽  
Forest Cover ◽  
Temporal Dynamics ◽  
Climatic Conditions ◽  
Burned Area ◽  
Secondary Forests ◽  
Forest Change ◽  
Mato Grosso ◽  
Area Data ◽  
Forest Cover Loss

Abstract. Fires are used as a tool in the deforestation process. Yet, the relationship between fire and deforestation may vary temporally and spatially depending on the type of deforestation and climatic conditions. This study evaluates spatiotemporal dynamics of deforestation and fire represented by burned area over the 2002–2012 period in the Brazilian Legal Amazon. As a first step, we compared newly available Landsat-based maps of gross forest cover loss from the Global Forest Change (GFC) project with maps of deforestation extent from the Amazon Deforestation Monitoring Project (PRODES) produced by the Brazilian National Institute for Space Research (INPE). As a second step, we rescaled the Landsat-based data to the 500 m resolution of the Moderate Resolution Imaging Spectroradiometer (MODIS) burned area data (MCD64A1) and stratified this using MODIS land cover data to study the role of burned area in forest cover loss and deforestation. We found that while GFC forest cover loss and PRODES deforestation generally agreed on spatial and temporal dynamics, there were several key differences between the data sets. Both showed a decrease in the extent of forest cover loss or deforestation after 2004, but the drop was larger and more continuous in PRODES than in GFC. The observed decrease in forest cover loss or deforestation rates over our study period was mainly due to lower clearing rates in the evergreen broadleaf forests in the states of Mato Grosso, Pará, and Rondônia. GFC indicated anomalously high forest cover loss in the years 2007 and 2010, which was not reported by PRODES. The burned area data indicated that this was predominantly related to increased burned area occurring outside of the tropical forest area during these dry years, mainly in Pará. This indicated that fire and forest loss dynamics in woodlands or secondary forests may be equally important as deforestation in regulating atmospheric CO2 concentrations. In addition to the decrease in forest cover loss rates, we also found that post-deforestation fire use declined; burned area within 5 years after forest cover loss decreased from 54 to 39 % during our study period.

Assessing climate impact on forest cover in areas undergoing substantial land cover change using Landsat imagery

2019 ◽  
Vol 659 ◽  
pp. 732-745 ◽  
Author(s):  
Qinli Yang ◽  
Heng Zhang ◽  
Wanshan Peng ◽  
Yaoyao Lan ◽  
Shasha Luo ◽  
...  
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Forest Cover ◽  
Landsat Imagery ◽  
Climate Impact

scholarly journals Impact of land-use change on catchment water balance: a case study in the central region of South Africa

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yali E. Woyessa ◽  
Worku A. Welderufael
Keyword(s):  
South Africa ◽  
Land Use ◽  
Water Balance ◽  
Central Region ◽  
Surface Runoff ◽  
Catchment Area ◽  
Forest Cover ◽  
Water Yield ◽  
Climatic Data ◽  
The Mean

AbstractAn assessment study on the impact of land use change through afforestation on catchment water balance was carried out in one of the semi-arid quaternary catchments (C52A) of the Modder River Basin located in the central region of South Africa. The study used ArcGIS and the Soil and Water Assessment Tool (SWAT) to create scenarios of forest cover areas and to simulate the water balance of C52A, respectively. Climatic data from 1993 to 2020 were used to simulate the catchment water balance. The climatic data from 2011 to 2020 were generated using SWAT weather generator while the rest was obtained from South Africa Weather Service at three weather stations located within C52A catchment. In the C52A quaternary catchment it was envisaged to increase forest cover by considering afforestation on pastureland that is found on slopes > 8% and > 3% which created two forest scenarios. The baseline land use [Land use 2000 (LU2000)] which is taken as the base scenario in this study has about 84% of the catchment area covered with pasture. The two forest scenarios created were: forest scenario1 (FRSE1), i.e. conversion of pastureland on slope > 8% to forest, and forest scenario2 (FRSE2), i.e. conversion of pastureland on slope > 3% to forest. The type of forest considered in these scenarios is an evergreen tree, acronym as FRSE by SWAT land use classification. The conversion increased forest cover by 8.3% and 30.5% on FRSE1 and FRSE2, respectively. The result of the water balance of the catchment based on the land use scenarios were compared with the baseline land use scenario (LU2000). The result obtained showed that FRSE1 produced a non-significant change both on the mean monthly surface runoff and water yield compared to LU2000. On the other hand, FRSE2 showed 30% decrease on the mean monthly surface runoff, but increased the mean monthly lateral flow and base flow by 110% and 254%, respectively compared to the LU2000. Thus, in the overall water balance, the mean monthly water yield of the catchment increased by 171% on FRSE2 compared to the LU2000. Although there are considerable number of research reports on the negative effect of forest on catchment water yield, this study showed a significant water yield increase when approximately 30% of the C52A catchment area, which lay on slopes > 3% and covered by grass, was converted to evergreen forest land. The result showed that having a forest cover on a suitable slope range can bring about a positive effect on the total water yield of a catchment. Therefore, this finding is important for catchment management stakeholders and policy-makers when devising land use and water resources management strategies in a catchment.

scholarly journals Evaluating Forest Cover and Fragmentation in Costa Rica with a Corrected Global Tree Cover Map

2020 ◽  
Vol 12 (19) ◽  
pp. 3226
Author(s):  
Daniel Cunningham ◽  
Paul Cunningham ◽  
Matthew E. Fagan
Keyword(s):  
Costa Rica ◽  
Forest Cover ◽  
Agricultural Land ◽  
Forest Area ◽  
Tree Cover ◽  
Agricultural Crop ◽  
Forest Change ◽  
Alos Palsar ◽  
Tropical Regions ◽  
The Impact

Global tree cover products face challenges in accurately predicting tree cover across biophysical gradients, such as precipitation or agricultural cover. To generate a natural forest cover map for Costa Rica, biases in tree cover estimation in the most widely used tree cover product (the Global Forest Change product (GFC) were quantified and corrected, and the impact of map biases on estimates of forest cover and fragmentation was examined. First, a forest reference dataset was developed to examine how the difference between reference and GFC-predicted tree cover estimates varied along gradients of precipitation and elevation, and nonlinear statistical models were fit to predict the bias. Next, an agricultural land cover map was generated by classifying Landsat and ALOS PalSAR imagery (overall accuracy of 97%) to allow removing six common agricultural crops from estimates of tree cover. Finally, the GFC product was corrected through an integrated process using the nonlinear predictions of precipitation and elevation biases and the agricultural crop map as inputs. The accuracy of tree cover prediction increased by ≈29% over the original global forest change product (the R2 rose from 0.416 to 0.538). Using an optimized 89% tree cover threshold to create a forest/nonforest map, we found that fragmentation declined and core forest area and connectivity increased in the corrected forest cover map, especially in dry tropical forests, protected areas, and designated habitat corridors. By contrast, the core forest area decreased locally where agricultural fields were removed from estimates of natural tree cover. This research demonstrates a simple, transferable methodology to correct for observed biases in the Global Forest Change product. The use of uncorrected tree cover products may markedly over- or underestimate forest cover and fragmentation, especially in tropical regions with low precipitation, significant topography, and/or perennial agricultural production.

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