Atmosphere–land interactions simulated by an LES model are evaluated from the perspective of heterogeneity propagation by comparison with airborne measurements. It is found that the footprints of surface heterogeneit...Atmosphere–land interactions simulated by an LES model are evaluated from the perspective of heterogeneity propagation by comparison with airborne measurements. It is found that the footprints of surface heterogeneity, though as 2D patterns can be dissipated quickly due to turbulent mixing, as 1D projections can persist and propagate to the top of the atmospheric boundary layer. Direct comparison and length scale analysis show that the simulated heterogeneity patterns are comparable to the observation. The results highlight the model's capability in simulating the complex effects of surface heterogeneity on atmosphere–land interactions.展开更多
Most large-scale evapotranspiration(ET)estimation methods require detailed information of land use,land cover,and/or soil type on top of various atmospheric measurements.The complementary relationship of evaporation(C...Most large-scale evapotranspiration(ET)estimation methods require detailed information of land use,land cover,and/or soil type on top of various atmospheric measurements.The complementary relationship of evaporation(CR)takes advantage of the inherent dynamic feedback mechanisms found in the soil−vegetation−atmosphere interface for its estimation of ET rates without the need of such biogeophysical data.ET estimates over the conterminous United States by a new,globally calibrated,static scaling(GCR-stat)of the generalized complementary relationship(GCR)of evaporation were compared to similar estimates of an existing,calibration-free version(GCR-dyn)of the GCR that employs a temporally varying dynamic scaling.Simplified annual water balances of 327 medium and 18 large watersheds served as ground-truth ET values.With long-term monthly mean forcing,GCR-stat(also utilizing precipitation measurements)outperforms GCR-dyn as the latter cannot fully take advantage of its dynamic scaling with such data of reduced temporal variability.However,in a continuous monthly simulation,GCR-dyn is on a par with GCR-stat,and especially excels in reproducing long-term tendencies in annual catchment ET rates even though it does not require precipitation information.The same GCR-dyn estimates were also compared to similar estimates of eight other popular ET products and they generally outperform all of them.For this reason,a dynamic scaling of the GCR is recommended over a static one for modeling long-term behavior of terrestrial ET.展开更多
基金supported by the DFG Transregional Cooperative Research Centre 32 "Patterns in Soil-Vegetation-Atmosphere-Systems: Monitoring, Modelling and Data Assimilation"
文摘Atmosphere–land interactions simulated by an LES model are evaluated from the perspective of heterogeneity propagation by comparison with airborne measurements. It is found that the footprints of surface heterogeneity, though as 2D patterns can be dissipated quickly due to turbulent mixing, as 1D projections can persist and propagate to the top of the atmospheric boundary layer. Direct comparison and length scale analysis show that the simulated heterogeneity patterns are comparable to the observation. The results highlight the model's capability in simulating the complex effects of surface heterogeneity on atmosphere–land interactions.
基金supported by a BMEWater Sciences and Disaster Prevention FIKP grant of EMMI(BME FIKP-VIZ).
文摘Most large-scale evapotranspiration(ET)estimation methods require detailed information of land use,land cover,and/or soil type on top of various atmospheric measurements.The complementary relationship of evaporation(CR)takes advantage of the inherent dynamic feedback mechanisms found in the soil−vegetation−atmosphere interface for its estimation of ET rates without the need of such biogeophysical data.ET estimates over the conterminous United States by a new,globally calibrated,static scaling(GCR-stat)of the generalized complementary relationship(GCR)of evaporation were compared to similar estimates of an existing,calibration-free version(GCR-dyn)of the GCR that employs a temporally varying dynamic scaling.Simplified annual water balances of 327 medium and 18 large watersheds served as ground-truth ET values.With long-term monthly mean forcing,GCR-stat(also utilizing precipitation measurements)outperforms GCR-dyn as the latter cannot fully take advantage of its dynamic scaling with such data of reduced temporal variability.However,in a continuous monthly simulation,GCR-dyn is on a par with GCR-stat,and especially excels in reproducing long-term tendencies in annual catchment ET rates even though it does not require precipitation information.The same GCR-dyn estimates were also compared to similar estimates of eight other popular ET products and they generally outperform all of them.For this reason,a dynamic scaling of the GCR is recommended over a static one for modeling long-term behavior of terrestrial ET.