scholarly journals Functional convergence of biosphere–atmosphere interactions in response to meteorology

2020 ◽  
Author(s):  
Christopher Krich ◽  
Mirco Migliavacca ◽  
Diego G. Miralles ◽  
Guido Kraemer ◽  
Tarek S. El-Madany ◽  
...  
Keyword(s):  
Land Surface ◽  
Water Cycle ◽  
Causal Structure ◽  
Terrestrial Ecosystems ◽  
Mediterranean Ecosystems ◽  
Meteorological Conditions ◽  
Surface Fluxes ◽  
Vegetation Types ◽  
Climatic Regions ◽  
Novel Algorithms

Abstract. Understanding the dependencies of the terrestrial carbon and water cycle is a prerequisite to anticipate their behaviour under climate change conditions. However, terrestrial ecosystems and the atmosphere interact via a multitude of variables, time- and space scales. Additionally the interactions might differ among vegetation types or climatic regions. Today, novel algorithms aim to disentangle the causal structure behind such interaction from empirical data. Visualising the estimated structure in networks, the nodes represent relevant meteorological determinants and land-surface fluxes, and the links dependencies among them possibly including their lag and strength. Here we show that biosphere–atmosphere interactions are strongly shaped by meteorological conditions. For example, we find that temperate and high latitude ecosystems during peak productivity exhibit very similar biosphere–atmosphere interaction networks as tropical forests. In times of anomalous conditions like drought though, both ecosystems behave more like Mediterranean ecosystems during their dry season. Our results demonstrate that ecosystems from different climate or vegetation types have similar biosphere–atmosphere interactions if their meteorological conditions are similar. We anticipate our analysis to foster the use of network approaches as they allow a more comprehensive understanding of the state of ecosystem functioning. Long term or even irreversible changes in network structure are rare and thus can be indicators of fundamental functional ecosystem shifts.

scholarly journals Functional convergence of biosphere–atmosphere interactions in response to meteorological conditions

2021 ◽  
Vol 18 (7) ◽  
pp. 2379-2404
Author(s):  
Christopher Krich ◽  
Mirco Migliavacca ◽  
Diego G. Miralles ◽  
Guido Kraemer ◽  
Tarek S. El-Madany ◽  
...  
Keyword(s):  
Land Surface ◽  
Water Cycle ◽  
Causal Structure ◽  
Spatial Scales ◽  
Terrestrial Ecosystems ◽  
Mediterranean Ecosystems ◽  
Meteorological Conditions ◽  
Surface Fluxes ◽  
Time Lags ◽  
Vegetation Types

Abstract. Understanding the dependencies of the terrestrial carbon and water cycle with meteorological conditions is a prerequisite to anticipate their behaviour under climate change conditions. However, terrestrial ecosystems and the atmosphere interact via a multitude of variables across temporal and spatial scales. Additionally these interactions might differ among vegetation types or climatic regions. Today, novel algorithms aim to disentangle the causal structure behind such interactions from empirical data. The estimated causal structures can be interpreted as networks, where nodes represent relevant meteorological variables or land-surface fluxes and the links represent the dependencies among them (possibly including time lags and link strength). Here we derived causal networks for different seasons at 119 eddy covariance flux tower observations in the FLUXNET network. We show that the networks of biosphere–atmosphere interactions are strongly shaped by meteorological conditions. For example, we find that temperate and high-latitude ecosystems during peak productivity exhibit biosphere–atmosphere interaction networks very similar to tropical forests. In times of anomalous conditions like droughts though, both ecosystems behave more like typical Mediterranean ecosystems during their dry season. Our results demonstrate that ecosystems from different climate zones or vegetation types have similar biosphere–atmosphere interactions if their meteorological conditions are similar. We anticipate our analysis to foster the use of network approaches, as they allow for a more comprehensive understanding of the state of ecosystem functioning. Long-term or even irreversible changes in network structure are rare and thus can be indicators of fundamental functional ecosystem shifts.

scholarly journals Vegetation dynamics and soil water balance in a water-limited Mediterranean ecosystem on Sardinia, Italy

2008 ◽  
Vol 12 (6) ◽  
pp. 1257-1271 ◽  
Author(s):  
N. Montaldo ◽  
J. D. Albertson ◽  
M. Mancini
Keyword(s):  
Soil Water ◽  
Land Surface ◽  
Vegetation Dynamics ◽  
Mediterranean Ecosystems ◽  
Surface Fluxes ◽  
Annual Rainfall ◽  
Woody Vegetation ◽  
Wide Range ◽  
Hydrometeorological Conditions

Abstract. Mediterranean ecosystems are commonly heterogeneous savanna-like ecosystems, with contrasting plant functional types (PFTs, e.g. grass and woody vegetation) competing for water. Mediterranean ecosystems are also commonly characterized by strong inter-annual rainfall variability, which influences the distributions of PFTs that vary spatially and temporally. An extensive field campaign in a Mediterranean setting was performed with the objective to investigate interactions between vegetation dynamics, soil water budget and land-surface fluxes in a water-limited ecosystem. Also a vegetation dynamic model (VDM) is coupled to a 3-component (bare soil, grass and woody vegetation) Land surface model (LSM). The case study is in Orroli, situated in the mid-west of Sardegna within the Flumendosa river basin. The landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and cork oaks, different shrubs and herbaceous species. Land surface fluxes, soil moisture and vegetation growth were monitored during the May 2003–June 2006 period. Interestingly, hydrometeorological conditions of the monitored years strongly differ, with dry and wet years in turn, such that a wide range of hydrometeorological conditions can be analyzed. The coupled VDM-LSM model is successfully tested for the case study, demonstrating high model performance for the wide range of eco-hydrologic conditions. Results demonstrate also that vegetation dynamics are strongly influenced by the inter-annual variability of atmospheric forcing, with grass leaf area index changing significantly each spring season according to seasonal rainfall amount.

Ecohydrology

2019 ◽  
Author(s):  
Valeriy Ivanov ◽  
Simone Fatichi ◽  
Edoardo Daly
Keyword(s):  
Water Resource Management ◽  
Water Cycle ◽  
Water Flux ◽  
Terrestrial Ecosystems ◽  
Limiting Factor ◽  
Atmospheric Sciences ◽  
Abiotic Environment ◽  
Vegetation Control ◽  
Climatic Regions ◽  
Interdisciplinary Field

Ecohydrology is a cross-disciplinary field that emerged in the early 2000s as a result of recognition of the need to better understand complex, multifaceted interactions occurring in terrestrial ecosystems and their connection to the water cycle. In this article, ecohydrology is viewed as the science that studies how water in all its forms links living organisms and their abiotic environment to define their function, interactions, structure, and distribution. As a highly interdisciplinary field, ecohydrology draws from hydrology, ecology, atmospheric sciences, plant ecophysiology, biophysics, hydrodynamics, soil science, geomorphology, biogeochemistry, agronomy, and even landscape architecture. Basic science questions and land and water resource management issues are addressed in the field. A range of temporal scales, from minutes (such as in stomatal response to a changing environment) to millennia (such as that characteristic of landscape evolution period), is relevant to studies in ecohydrology. Likewise, spatial extent of analysis covers a spectrum ranging from ~10–6 m (e.g., concerned with leaf stomatal cavities or soil pores), to regional scales at ~106 m. As other sciences, ecohydrologic research relies on theoretical analysis, observation-based inference and experimentation, and computational approaches. The latter are becoming powerful, permitting experimentation and tests of mathematical descriptions of relevant processes and mechanisms. As evidenced by the publication record, one the main scopes of ecohydrology has been to understand how water available to ecosystems is used by vegetation and impacts the water cycle through the process of evapotranspiration. This review draws from this literature thus having a prevailing emphasis on vegetation control of water fluxes (i.e., transpiration) and the bilateral interactions between vegetation and abiotic environment. This perspective is justified by the key role of transpiration in the water cycle: it is the largest water flux from vegetated land to the atmosphere. The field of ecohydrology has analyzed different climatic regions and areas. Arid and semiarid ecosystems, where water is the major limiting factor of ecosystem functioning, are viewed as one of the key foci in ecohydrologic studies, largely driving the establishment of the field. The role that transpiration has on rainfall via water recirculation and the potential effects of deforestation are the emphasis of tropical ecohydrology. The large changes in the hydrologic budget associated with urbanization are addressed in urban ecohydrologic studies. One may expect that future focus will be on understanding of the transformation of terrestrial ecosystems, as we know them, due to ongoing and anticipated changes in the hydrologic cycle.

scholarly journals Hydroclimatology of the Nile: results from a regional climate model

2005 ◽  
Vol 2 (1) ◽  
pp. 319-364 ◽  
Author(s):  
Y. A. Mohamed ◽  
B. J. J. M. van den Hurk ◽  
H. H. G. Savenije ◽  
W. G. M. Bastiaanssen
Keyword(s):  
Land Surface ◽  
Climate Model ◽  
Water Cycle ◽  
Regional Climate ◽  
Hydrologic Model ◽  
Surface Fluxes ◽  
Monthly Precipitation ◽  
Moisture Recycling ◽  
White Nile ◽  
Regional Water

Abstract. This paper is the result of the first regional coupled climatic and hydrologic model of the Nile. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are surprisingly accurate given the extremely low runoff coefficients in the catchment. The paper presents model results over the sub-basins: Blue Nile, White Nile, Atbara river and the Main Nile for the period 1995 to 2000, but focuses on the Sudd swamp. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation) over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.

scholarly journals Vegetation dynamics and soil water balance in a water-limited Mediterranean ecosystem on Sardinia, Italy

2008 ◽  
Vol 5 (1) ◽  
pp. 219-255 ◽  
Author(s):  
N. Montaldo ◽  
J. D. Albertson ◽  
M. Mancini
Keyword(s):  
Soil Water ◽  
Land Surface ◽  
Vegetation Dynamics ◽  
Mediterranean Ecosystems ◽  
Surface Fluxes ◽  
Annual Rainfall ◽  
Woody Vegetation ◽  
Wide Range ◽  
Hydrometeorological Conditions

Abstract. Mediterranean ecosystems are commonly heterogeneous savanna-like ecosystems, with contrasting plant functional types (PFTs, e.g., grass and woody vegetation) competing for the water use. Mediterranean ecosystems are also commonly characterized by strong inter-annual rainfall variability, which influences the distributions of PFTs that vary spatially and temporally. With the objective to investigate interactions between vegetation dynamics, soil water budget and land-surface fluxes in a water-limited ecosystem, an extensive field campaign in a Mediterranean setting was performed. Also a vegetation dynamic model (VDM) is coupled to a 3-component (bare soil, grass and woody vegetation) Land surface model (LSM). The case study is in Orroli, situated in the mid-west of Sardegna within the Flumendosa river basin. The landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and cork oaks, different shrubs and herbaceous species. Land surface fluxes, soil moisture and vegetation growth were monitored during the May 2003–June 2006 period. Interestingly, hydrometeorological conditions of the monitored years strongly differ, with dry and wet years in turn, such that a wide range of hydrometeorological conditions can be analyzed. The coupled VDM-LSM model is successfully tested for the case study, demonstrating high model performance for the wide range of eco-hydrologic conditions. The use of the VDM in the LSM is demonstrated to be essential when studying the climate-soil-vegetation interactions of these water-limited ecosystems. Results demonstrate also that vegetation dynamics are strongly influenced by the inter-annual variability of atmospheric forcing, with grass leaf area index changing significantly each spring season according to seasonal rainfall amount.

scholarly journals Hydroclimatology of the Nile: results from a regional climate model

2005 ◽  
Vol 9 (3) ◽  
pp. 263-278 ◽  
Author(s):  
Y. A. Mohamed ◽  
B. J. J. M. van den Hurk ◽  
H. H. G. Savenije ◽  
W. G. M. Bastiaanssen
Keyword(s):  
Land Surface ◽  
Climate Model ◽  
Water Cycle ◽  
Regional Climate ◽  
Hydrologic Model ◽  
Surface Fluxes ◽  
Monthly Precipitation ◽  
Nile Basin ◽  
Moisture Recycling ◽  
Regional Water

Abstract. This paper presents the result of the regional coupled climatic and hydrologic model of the Nile Basin. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are quite satisfactory given the extremely low runoff coefficients in the catchment. The paper presents the validation results over the sub-basins: Blue Nile, White Nile, Atbara river, the Sudd swamps, and the Main Nile for the period 1995 to 2000. Observational datasets were used to evaluate the model results including radiation, precipitation, runoff and evaporation data. The evaporation data were derived from satellite images over a major part of the Upper Nile. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The sources of atmospheric moisture to the basin, and location of convergence/divergence fields could be accurately illustrated. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation) over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.

Correction to “Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature”

2007 ◽  
Vol 112 (D6) ◽  
Author(s):  
Lianhong Gu ◽  
Tilden Meyers ◽  
Stephen G. Pallardy ◽  
Paul J. Hanson ◽  
Bai Yang ◽  
...  
Keyword(s):  
Land Surface ◽  
Surface Fluxes ◽  
Radiative Temperature

scholarly journals Discontinuous Daily Temperatures in the WATCH Forcing Datasets

2015 ◽  
Vol 16 (1) ◽  
pp. 465-472 ◽  
Author(s):  
Henning W. Rust ◽  
Tim Kruschke ◽  
Andreas Dobler ◽  
Madlen Fischer ◽  
Uwe Ulbrich
Keyword(s):  
Land Surface ◽  
Water Cycle ◽  
Research Unit ◽  
Climatic Research Unit ◽  
Daily Maximum ◽  
Monthly Means ◽  
Tropical Africa ◽  
Average Temperature ◽  
Surface Models ◽  
The Tropics

Abstract The Water and Global Change (WATCH) forcing datasets have been created to support the use of hydrological and land surface models for the assessment of the water cycle within climate change studies. They are based on 40-yr ECMWF Re-Analysis (ERA-40) or ECMWF interim reanalysis (ERA-Interim) with temperatures (among other variables) adjusted such that their monthly means match the monthly temperature dataset from the Climatic Research Unit. To this end, daily minimum, maximum, and mean temperatures within one calendar month have been subjected to a correction involving monthly means of the respective month. As these corrections can be largely different for adjacent months, this procedure potentially leads to implausible differences in daily temperatures across the boundaries of calendar months. We analyze day-to-day temperature fluctuations within and across months and find that across-months differences are significantly larger, mostly in the tropics and frigid zones. Average across-months differences in daily mean temperature are typically between 10% and 40% larger than their corresponding within-months average temperature differences. However, regions with differences up to 200% can be found in tropical Africa. Particularly in regions where snowmelt is a relevant player for hydrology, a few degrees Celsius difference can be decisive for triggering this process. Daily maximum and minimum temperatures are affected in the same regions, but in a less severe way.

Sign in / Sign up

Export Citation Format

Share Document