scholarly journals Water balance of the Amazon Basin: Dependence on vegetation cover and canopy conductance

1997 ◽  
Vol 102 (D20) ◽  
pp. 23973-23989 ◽  
Author(s):  
Marcos Heil Costa ◽  
Jonathan A. Foley
Keyword(s):  
Water Balance ◽  
Vegetation Cover ◽  
Amazon Basin ◽  
Canopy Conductance

scholarly journals Assessing the impact of climate variability on catchment water balance and vegetation cover

2011 ◽  
Vol 8 (3) ◽  
pp. 6291-6329 ◽  
Author(s):  
X. Xu ◽  
D. Yang ◽  
M. Sivapalan
Keyword(s):  
Statistical Analysis ◽  
Water Balance ◽  
Climate Variability ◽  
Vegetation Cover ◽  
Growing Season ◽  
Woody Vegetation ◽  
Elasticity Analysis ◽  
Total Runoff ◽  
Subsurface Runoff ◽  
Growing Season Precipitation

Abstract. Understanding the interactions among climate, vegetation cover and the water cycle lies at the heart of the study of watershed ecohydrology. Recently, considerable attention is being paid to the effect of climate variability (e.g., precipitation and temperature) on catchment water balance and also associated vegetation cover. In this paper, we investigate the general pattern of long-term water balance and vegetation cover (as reflected in fPAR) among 193 study catchments in Australia through statistical analysis. We then employ the elasticity analysis approach for quantifying the effects of climate variability on hydrologic partitioning (including total runoff, surface and subsurface runoff) and on vegetation cover (including total, woody and non-woody vegetation cover). Based on the results of statistical analysis, we conclude that annual runoff (R), evapotranspiration (E) and runoff coefficient (R/P) all increase with vegetation cover for catchments in which woody vegetation is dominant and annual precipitation is relatively high. Annual evapotranspiration (E) is mainly controlled by water availability rather than energy availability for catchments in relatively dry climates in which non-woody vegetation is dominant. The ratio of subsurface runoff to total runoff (Rg/R) also increases with woody vegetation cover. Through the elasticity analysis of catchment runoff, it is shown that precipitation (P) in the current year is the most important factor affecting the change in annual total runoff (R), surface runoff (Rs) and subsurface runoff (Rg). The significance of other controlling factors is in the order of the annual precipitation in the previous year (P−1 and P−2), which represent the net effect of soil moisture, and the annual mean temperature (T) in the current year. Change of P by +1 % causes a +3.35 % change of R, a +3.47 % change of Rs and a +2.89 % change of Rg, on average. Likewise a change of temperature of +1° causes a −0.05 % change of R, a −0.07 % change of Rs and a −0.10 % change of Rg, on average. Results of elasticity analysis on the maximum monthly vegetation cover indicate that incoming shortwave radiation during the growing season (Rsd,grow) is the most important factor affecting the change in vegetation cover. Change of Rsd,grow by +1 % produces a −1.08 % change of total vegetation cover (Ft) on average. The significance of other causative factors is in the order of the precipitation during growing season, mean temperature during growing season and precipitation during non-growing season. The growing season precipitation is more significant than the non-growing season precipitation to non-woody vegetation cover, but the both have equivalent effects to woody vegetation cover.

scholarly journals Measuring and modeling water-related soil–vegetation feedbacks in a fallow plot

2014 ◽  
Vol 18 (3) ◽  
pp. 1105-1118 ◽  
Author(s):  
N. Ursino ◽  
G. Cassiani ◽  
R. Deiana ◽  
G. Vignoli ◽  
J. Boaga
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Vegetation Cover ◽  
Water Cycle ◽  
Geophysical Methods ◽  
Vegetation Feedback ◽  
Weed Growth ◽  
Local Soil ◽  
Soil Saturation ◽  
The Impact

Abstract. Land fallowing is one possible response to shortage of water for irrigation. Leaving the soil unseeded implies a change of the soil functioning that has an impact on the water cycle. The development of a soil crust in the open spaces between the patterns of grass weed affects the soil properties and the field-scale water balance. The objectives of this study are to test the potential of integrated non-invasive geophysical methods and ground-image analysis and to quantify the effect of the soil–vegetation interaction on the water balance of fallow land at the local- and plot scale. We measured repeatedly in space and time local soil saturation and vegetation cover over two small plots located in southern Sardinia, Italy, during a controlled irrigation experiment. One plot was left unseeded and the other was cultivated. The comparative analysis of ERT maps of soil moisture evidenced a considerably different hydrologic response to irrigation of the two plots. Local measurements of soil saturation and vegetation cover were repeated in space to evidence a positive feedback between weed growth and infiltration at the fallow plot. A simple bucket model captured the different soil moisture dynamics at the two plots during the infiltration experiment and was used to estimate the impact of the soil vegetation feedback on the yearly water balance at the fallow site.

WATER BALANCE DELINEATES THE SOIL LAYER IN WHICH MOISTURE AFFECTS CANOPY CONDUCTANCE

1998 ◽  
Vol 8 (4) ◽  
pp. 990-1002 ◽  
Author(s):  
Ram Oren ◽  
Brent E. Ewers ◽  
Philip Todd ◽  
Nathan Phillips ◽  
Gabriel Katul
Keyword(s):  
Water Balance ◽  
Soil Layer ◽  
Canopy Conductance

scholarly journals Global 5-km resolution estimates of secondary evaporation including irrigation through satellite data assimilation

2018 ◽  
Author(s):  
Albert I. J. M. van Dijk ◽  
Jaap Schellekens ◽  
Marta Yebra ◽  
Hylke E. Beck ◽  
Luigi J. Renzullo ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Data Assimilation ◽  
Water Balance ◽  
Irrigation Water ◽  
Water Bodies ◽  
Estimation Methods ◽  
Canopy Conductance ◽  
Area Index ◽  
Secondary Evaporation

Abstract. A portion of globally generated surface and groundwater resources evaporates from wetlands, water bodies and irrigated areas. This secondary evaporation of blue water directly affects the remaining water resources available for ecosystems and human use. At the global scale, a lack of detailed water balance studies and direct observations limits our understanding of the magnitude and spatial and temporal distribution of secondary evaporation. Here, we propose a methodology to assimilate satellite-derived information into the landscape hydrological model W3 at an unprecedented 0.05° or c. 5 km resolution globally. The assimilated data are all derived from MODIS observations, including surface water extent, surface albedo, vegetation cover, leaf area index, canopy conductance, and land surface temperature (LST). The information from these products is imparted on the model in a simple but efficient manner, through a combination of direct insertion of surface water extent, evaporation flux adjustment based on LST, and parameter nudging for the other observations. The resulting water balance estimates were evaluated against river basin discharge records and the water balance of closed basins and demonstrably improved water balance estimates compared to ignoring secondary evaporation (e.g., bias improved from +38 mm/d to +2 mm/d). The evaporation estimates derived from assimilation were combined with global mapping of irrigation crops to derive a minimum estimate of irrigation water requirements (I0), representative of optimal irrigation efficiency. Our I0 estimates were lower than published country-level estimates of irrigation water use produced by alternative estimation methods, for reasons that are discussed. We estimate that 16 % of globally generated water resources evaporate before reaching the oceans, enhancing total terrestrial evaporation by 6.1 • 1012 m3 y−1 or 8.8 %. Of this volume, 5 % is evaporated from irrigation areas, 58% from terrestrial water bodies and 37 % from other surfaces. Model-data assimilation at even higher spatial resolutions can achieve a further reduction in uncertainty but will require more accurate and detailed mapping of surface water dynamics and areas equipped for irrigation.

scholarly journals Energy balance and canopy conductance of a tropical semi-deciduous forest of the southern Amazon Basin

2008 ◽  
Vol 44 (3) ◽  
Author(s):  
George L. Vourlitis ◽  
José de Souza Nogueira ◽  
Francisco de Almeida Lobo ◽  
Kerrie M. Sendall ◽  
Sérgio Roberto de Paulo ◽  
...  
Keyword(s):  
Energy Balance ◽  
Amazon Basin ◽  
Deciduous Forest ◽  
Canopy Conductance

scholarly journals Assessing the impact of climate variability on catchment water balance and vegetation cover

2012 ◽  
Vol 16 (1) ◽  
pp. 43-58 ◽  
Author(s):  
X. Xu ◽  
D. Yang ◽  
M. Sivapalan
Keyword(s):  
Statistical Analysis ◽  
Water Balance ◽  
Climate Variability ◽  
Vegetation Cover ◽  
Growing Season ◽  
Woody Vegetation ◽  
Elasticity Analysis ◽  
Total Runoff ◽  
Subsurface Runoff ◽  
Growing Season Precipitation

Abstract. Understanding the interactions among climate, vegetation cover and the water cycle lies at the heart of the study of watershed ecohydrology. Recently, considerable attention is being paid to the effect of climate variability on catchment water balance and also associated vegetation cover. In this paper, we investigate the general pattern of long-term water balance and vegetation cover (as reflected by fPAR) among 193 study catchments in Australia through statistical analysis. We then employ the elasticity analysis approach for quantifying the effects of climate variability on hydrologic partitioning (including total, surface and subsurface runoff) and on vegetation cover (including total, woody and non-woody vegetation cover). Based on the results of statistical analysis, we conclude that annual runoff (R), evapotranspiration (E) and runoff coefficient (R/P) increase with vegetation cover for catchments in which woody vegetation is dominant and annual precipitation is relatively high. Control of water available on annual evapotranspiration in non-woody dominated catchments is relatively stronger compared to woody dominated ones. The ratio of subsurface runoff to total runoff (Rg/R) also increases with woody vegetation cover. Through the elasticity analysis of catchment runoff, it is shown that precipitation (P) in current year is the most important factor affecting the change in annual total runoff (R), surface runoff (Rs) and subsurface runoff (Rg). The significance of other controlling factors is in the order of annual precipitation in previous years (P−1 and P−2), which represents the net effect of soil moisture and annual mean temperature (T) in current year. Change of P by +1% causes a +3.35% change of R, a +3.47% change of Rs and a +2.89% change of Rg, on average. Results of elasticity analysis on the maximum monthly vegetation cover indicate that incoming shortwave radiation during the growing season (Rsd,grow) is the most important factor affecting the change in vegetation cover. Change of Rsd,grow by +1% produces a −1.08% change of total vegetation cover (Ft) on average. The significance of other causative factors is in the order of precipitation during growing season, mean temperature during growing season and precipitation during non-growing season. Growing season precipitation is more significant than non-growing season precipitation to non-woody vegetation cover, but both have equivalent effects to woody vegetation cover.

scholarly journals REGREENING OF THE NORTHERN ETHIOPIAN MOUNTAINS: EFFECTS ON FLOODING AND ON WATER BALANCE

Afrika Focus ◽  
2019 ◽  
Vol 31 (2) ◽  
Author(s):  
Tesfaalem G. Asfaha ◽  
Michiel De Meyere ◽  
Amaury Frankl ◽  
Mitiku Haile ◽  
Jan Nyssen
Keyword(s):  
Water Balance ◽  
Vegetation Cover ◽  
Google Earth ◽  
Sediment Supply ◽  
Peak Discharge ◽  
Northern Ethiopia ◽  
Change Analysis ◽  
Aerial Photos ◽  
Bedload Sediment ◽  
The Impact

The hydro-geomorphology of mountain catchments is mainly determined by vegetation cover. This study was carried out to analyse the impact of vegetation cover dynamics on flooding and water balance in 11 steep (0.27-0.65 m m-1) catchments of the western Rift Valley escarpment of Northern Ethiopia, an area that experienced severe deforestation and degradation until the first half of the 1980s and considerable reforestation thereafter. Land cover change analysis was carried out using aerial photos (1936,1965 and 1986) and Google Earth imaging (2005 and 2014). Peak discharge heights of 332 events and the median diameter of the 10 coarsest bedload particles (Max10) moved in each event in three rainy seasons (2012-2014) were monitored. The result indicates a strong reduction in flooding (R2 = 0.85, P<0.01) and bedload sediment supply (R2 = 0.58, P<0.05) with increasing vegetation cover. Overall, this study demonstrates that in reforesting steep tropical mountain catchments, magnitude of flooding, water balance and bedload movement is strongly determined by vegetation cover dynamics. KEY WORDS: HYDRO-GEOMORPHOLOGY, REFORESTATION, CREST STAGE, PEAK DISCHARGE, BEDLOAD

scholarly journals Regreening of The Northern Ethiopian Mountains: Effects on Flooding and on Water Balance

Afrika Focus ◽  
2018 ◽  
Vol 31 (2) ◽  
pp. 129-147
Author(s):  
Tesfaalem G. Asfaha ◽  
Michiel De Meyere ◽  
Amaury Frankl ◽  
Mitiku Haile ◽  
Jan Nyssen
Keyword(s):  
Water Balance ◽  
Vegetation Cover ◽  
Google Earth ◽  
Sediment Supply ◽  
Northern Ethiopia ◽  
Change Analysis ◽  
Aerial Photos ◽  
Median Diameter ◽  
Bedload Sediment ◽  
The Impact

The hydro-geomorphology of mountain catchments is mainly determined by vegetation cover. This study was carried out to analyse the impact of vegetation cover dynamics on flooding and water balance in 11 steep (0.27-0.65 mm-1) catchments of the western Rift Valley escarpment of Northern Ethiopia, an area that experienced severe deforestation and degradation until the first half of the 1980s and considerable reforestation thereafter. Land cover change analysis was carried out using aerial photos (1936,1965 and 1986) and Google Earth imaging (2005 and 2014). Peak discharge heights of 332 events and the median diameter of the 10 coarsest bedload particles (Max10) moved in each event in three rainy seasons (2012-2014) were monitored. The result indicates a strong reduction in flooding (R2 = 0.85, P<0.01) and bedload sediment supply (R2 = 0.58, P<0.05) with increasing vegetation cover. Overall, this study demonstrates that in reforesting steep tropical mountain catchments, magnitude of flooding, water balance and bedload movement is strongly determined by vegetation cover dynamics.

scholarly journals Measuring and modelling water related soil–vegetation feedbacks in a fallow plot

2013 ◽  
Vol 10 (8) ◽  
pp. 11151-11184 ◽  
Author(s):  
N. Ursino ◽  
G. Cassiani ◽  
R. Deiana ◽  
G. Vignoli ◽  
J. Boaga
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Vegetation Cover ◽  
Water Cycle ◽  
Geophysical Methods ◽  
Vegetation Feedback ◽  
Weed Growth ◽  
Local Soil ◽  
Soil Saturation ◽  
The Impact

Abstract. Land fallowing is one possible response to shortage of water for irrigation. Leaving the soil unseeded implies a change of the soil functioning that has an impact on the water cycle. The development of a soil crust in the open spaces between the patterns of grass weed affects the soil properties and the field scale water balance. The objectives of this study are to test the potential of integrated non invasive geophysical methods and ground-image analysis and to quantify the effect of the soil vegetation interaction on the water balance of a fallow land at the local and plot scale. We measured repeatedly in space and time local soil saturation and vegetation cover over two small plots located in southern Sardinia, Italy, during a controlled irrigation experiment. One plot was left unseeded and the other was cultivated. The comparative analysis of ERT maps of soil moisture evidenced a considerably different hydrologic response to irrigation of the two plots. Local measurements of soil saturation and vegetation cover were repeated in space to evidence a positive feedback between weed growth and infiltration at the fallow plot. A simple bucket model captured the different soil moisture dynamics at the two plots during the infiltration experiment and was used to estimate the impact of the soil vegetation feedback on the yearly water balance at the fallow site.

LBA-ECO LC-15 VEGETATION COVER TYPES FROM MODIS, 1-KM, AMAZON BASIN: 2000-2001

2011 ◽  
Author(s):  
M.C. HANSEN, ◽  
M. CARROLL, ◽  
B. NELSON, ◽  
R.S. DeFries, ◽  
J.R.G. Townshend, ◽  
...  
Keyword(s):  
Vegetation Cover ◽  
Amazon Basin
Sign in / Sign up

Export Citation Format

Share Document