Radiative feedbacks on land surface change and associated tropical precipitation shifts

AbstractChanges in land surface albedo and land surface evaporation modulate the atmospheric energy budget by changing temperatures, water vapor, clouds, snow and ice cover, and the partitioning of surface energy fluxes. Here idealized perturbations to land surface properties are imposed in a global model to understand how such forcings drive shifts in zonal mean atmospheric energy transport and zonal mean tropical precipitation. For a uniform decrease in global land albedo, the albedo forcing and a positive water vapor feedback contribute roughly equally to increased energy absorption at the top of the atmosphere (TOA), while radiative changes due to the temperature and cloud cover response provide a negative feedback and energy loss at TOA. Decreasing land albedo causes a northwards shift in the zonal mean intertropical convergence zone (ITCZ). The combined effects on ITCZ location of all atmospheric feedbacks roughly cancel for the albedo forcing; the total ITCZ shift is comparable to that predicted for the albedo forcing alone. For an imposed increase in evaporative resistance that reduces land evaporation, low cloud cover decreases in the northern mid-latitudes and more energy is absorbed at TOA there; longwave loss due to warming provides a negative feedback on the TOA energy balance and ITCZ shift. Imposed changes in land albedo and evaporative resistance modulate fundamentally different aspects of the surface energy budget. However, the pattern of TOA radiation changes due to the water vapor and air temperature responses are highly correlated for these two forcings because both forcings lead to near-surface warming.

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Separating the Impact of Individual Land Surface Properties on the Terrestrial Surface Energy Budget in both the Coupled and Uncoupled Land–Atmosphere System

Journal of Climate ◽

10.1175/jcli-d-18-0812.1 ◽

2019 ◽

Vol 32 (18) ◽

pp. 5725-5744 ◽

Cited By ~ 15

Author(s):

Marysa M. Laguë ◽

Gordon B. Bonan ◽

Abigail L. S. Swann

Keyword(s):

Surface Energy ◽

Surface Temperature ◽

Surface Properties ◽

Energy Budget ◽

Land Surface ◽

Temperature Response ◽

Surface Energy Budget ◽

Evaporative Resistance ◽

Atmospheric Feedbacks ◽

The Impact

Abstract Changes in the land surface can drive large responses in the atmosphere on local, regional, and global scales. Surface properties control the partitioning of energy within the surface energy budget to fluxes of shortwave and longwave radiation, sensible and latent heat, and ground heat storage. Changes in surface energy fluxes can impact the atmosphere across scales through changes in temperature, cloud cover, and large-scale atmospheric circulation. We test the sensitivity of the atmosphere to global changes in three land surface properties: albedo, evaporative resistance, and surface roughness. We show the impact of changing these surface properties differs drastically between simulations run with an offline land model, compared to coupled land–atmosphere simulations that allow for atmospheric feedbacks associated with land–atmosphere coupling. Atmospheric feedbacks play a critical role in defining the temperature response to changes in albedo and evaporative resistance, particularly in the extratropics. More than 50% of the surface temperature response to changing albedo comes from atmospheric feedbacks in over 80% of land areas. In some regions, cloud feedbacks in response to increased evaporative resistance result in nearly 1 K of additional surface warming. In contrast, the magnitude of surface temperature responses to changes in vegetation height are comparable between offline and coupled simulations. We improve our fundamental understanding of how and why changes in vegetation cover drive responses in the atmosphere, and develop understanding of the role of individual land surface properties in controlling climate across spatial scales—critical to understanding the effects of land-use change on Earth’s climate.

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Case analyses and numerical simulation of soil thermal impacts on land surface energy budget based on an off-line land surface model

Advances in Atmospheric Sciences ◽

10.1007/s00376-002-0082-0 ◽

2002 ◽

Vol 19 (3) ◽

pp. 500-512 ◽

Cited By ~ 5

Author(s):

Guo Weidong ◽

Sun Shufen ◽

Qian Yongfu

Keyword(s):

Numerical Simulation ◽

Surface Energy ◽

Energy Budget ◽

Land Surface ◽

Land Surface Model ◽

Surface Energy Budget ◽

Surface Model

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The extreme Greenland melt season of 2019 in a 16-year time series of surface energy balance at the Kangerlussuaq transect

10.5194/egusphere-egu2020-15968 ◽

2020 ◽

Author(s):

Peter Kuipers Munneke ◽

Carleen Reijmer ◽

Paul Smeets ◽

Michiel van den Broeke

Keyword(s):

Time Series ◽

Surface Energy ◽

Energy Budget ◽

High Surface ◽

Greenland Ice Sheet ◽

Surface Energy Budget ◽

Strong Increase ◽

Near Surface ◽

Ablation Area ◽

Surface Melt

In 2019, the Kangerlussuaq transect has experienced a record surface melt season at some stations, exceeding even the melt seasons of 2010 and 2012. We demonstrate that net radiation has been driving the high surface melt rates especially in the higher parts of the transect.Since 2003, continuous measurements of the surface energy budget are made in a transect of four automatic weather stations, spanning the ablation area close to the ice edge to the accumulation are of the Greenland Ice Sheet. All available data have been homogenized and corrected, and an unprecedented time series of surface energy budget is presented here, including meltwater production. In this contribution, the melt season of 2019 is put into the longer-term context, and precise atmospheric drivers of the melt are exposed.Sixteen years of data clearly reveal the inland and upward expansion of the ablation area. The weather station closest to the equilibrium line (S9) shows a clear and distinct reduction in albedo, and a relatively strong increase in surface melt, which has started to exceed accumulation during the period of observation. Photographs of the area around S9 show that the surface has undergone major changes between 2003 and 2019, now featuring many surface hydrological features that were completely absent in 2003.These changes have important implications for the hydrology of the surface, the near-surface, and the underlying firn. A firn model calculation reveals that the entire firn column has been heating by several degrees Celsius in the percolation zone, due to refreezing of meltwater. Sudden, stepwise warming is seen in extreme melt seasons like 2019.

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Land Surface Energy Budget

Remote Sensing and Global Climate Change ◽

10.1007/978-3-642-79287-8_17 ◽

1994 ◽

pp. 367-391

Author(s):

H. Mannstein

Keyword(s):

Surface Energy ◽

Energy Budget ◽

Land Surface ◽

Surface Energy Budget

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Modeling the Near-Surface Energies and Water Vapor Fluxes Behavior in Response to Summer Canopy Density across Yanqi Endorheic Basin, Northwestern China

Remote Sensing ◽

10.3390/rs13183764 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3764

Author(s):

Patient Mindje Kayumba ◽

Gonghuan Fang ◽

Yaning Chen ◽

Richard Mind’je ◽

Yanan Hu ◽

...

Keyword(s):

Water Vapor ◽

Water Resources ◽

Surface Energy ◽

Northwestern China ◽

Energy Fluxes ◽

Evaporative Fraction ◽

Near Surface ◽

Available Energy ◽

Semi Arid

The Yanqi basin is the main irrigated and active agroecosystem in semi-arid Xinjiang, northwestern China, which further seeks responses to the profound local water-related drawbacks in relation to the unceasing landscape desiccation and scant precipitation. Yet, it comes as an astonishment that a few reported near-surface items and water vapor fluxes as so far required for water resources decision support, particularly in a scarce observation data region. As a contributive effort, here we adjusted the sensible heat flux (H) calibration mechanism of Surface Energy Balance Algorithm for Land (SEBAL) to high-resolution satellite dataset coupled with in-situ observation, through a wise guided “anchor” pixel assortment from surface reflectance-α, Leaf area index-LAI, vegetation index-NDVI, and surface temperature (Pcold, Phot) to model the robustness of energy fluxes and Evapotranspiration-ETa over the basin. Results reasonably reflected ETa which returned low RMSE (0.6 mm d−1), MAE (0.48 mm d−1) compared to in-situ recordings, indicating the competence of SEBAL to predict vapor fluxes in this region. The adjustment unveiled the estimates of the land-use contribution to evapotranspiration with an average ranging from 3 to 4.69 mm d−1, reaching a maximum of 5.5 mm d−1. Furthermore, findings showed a high striking energy dissipation (LE/Rn) across grasslands and wetlands. The vegetated surfaces with a great evaporative fraction were associated with the highest LE/Rn (70–90%), and water bodies varying between 20% and 60%, while the desert ecosystem dissipated the least energy with a low evaporative fraction. Still, besides high portrayed evaporation in water, grasslands and wetlands varied interchangeably in accounting for the highest ETa followed by cropland. Finally, a substantial nexus between available energy (Rn-G) and ETa informed the available energy, influenced by NDVI to be the primary driver of these oases’ transpiration. This study provides essentials of near-surface energy fluxes and the likelihood of ETa with considerable baseline inferences for Yanqi that may be beneficial for long-term investigations that will attend in agrometeorological services and sustainable management of water resources in semi-arid regions.

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Verification of Land–Atmosphere Coupling in Forecast Models, Reanalyses, and Land Surface Models Using Flux Site Observations

Journal of Hydrometeorology ◽

10.1175/jhm-d-17-0152.1 ◽

2018 ◽

Vol 19 (2) ◽

pp. 375-392 ◽

Cited By ~ 28

Author(s):

Paul A. Dirmeyer ◽

Liang Chen ◽

Jiexia Wu ◽

Chul-Su Shin ◽

Bohua Huang ◽

...

Keyword(s):

Surface Energy ◽

Land Surface ◽

Model Development ◽

Surface Flux ◽

Surface Fluxes ◽

Model Systems ◽

Shortwave Radiation ◽

Spatial And Temporal Variability ◽

Near Surface ◽

Flux Tower

Abstract This study compares four model systems in three configurations (LSM, LSM + GCM, and reanalysis) with global flux tower observations to validate states, surface fluxes, and coupling indices between land and atmosphere. Models clearly underrepresent the feedback of surface fluxes on boundary layer properties (the atmospheric leg of land–atmosphere coupling) and may overrepresent the connection between soil moisture and surface fluxes (the terrestrial leg). Models generally underrepresent spatial and temporal variability relative to observations, which is at least partially an artifact of the differences in spatial scale between model grid boxes and flux tower footprints. All models bias high in near-surface humidity and downward shortwave radiation, struggle to represent precipitation accurately, and show serious problems in reproducing surface albedos. These errors create challenges for models to partition surface energy properly, and errors are traceable through the surface energy and water cycles. The spatial distribution of the amplitude and phase of annual cycles (first harmonic) are generally well reproduced, but the biases in means tend to reflect in these amplitudes. Interannual variability is also a challenge for models to reproduce. Although the models validate better against Bowen-ratio-corrected surface flux observations, which allow for closure of surface energy balances at flux tower sites, it is not clear whether the corrected fluxes are more representative of actual fluxes. The analysis illuminates targets for coupled land–atmosphere model development, as well as the value of long-term globally distributed observational monitoring.

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Land-atmosphere interactions in an high resolution atmospheric simulation coupled with a surface data assimilation scheme

Natural Hazards and Earth System Science ◽

10.5194/nhess-9-1613-2009 ◽

2009 ◽

Vol 9 (5) ◽

pp. 1613-1624 ◽

Cited By ~ 8

Author(s):

L. Campo ◽

F. Castelli ◽

D. Entekhabi ◽

F. Caparrini

Keyword(s):

Energy Balance ◽

Data Assimilation ◽

Surface Energy ◽

Energy Budget ◽

Land Surface ◽

Surface States ◽

Atmospheric Model ◽

Turbulent Fluxes ◽

Data Assimilation Scheme ◽

Assimilation Scheme

Abstract. A valid tool for the retrieving of the turbulent fluxes that characterize the surface energy budget is constituted by the remote sensing of land surface states. In this study sequences of satellite-derived observations (from SEVIRI sensors aboard the Meteosat Second Generation) of Land Surface Temperature have been used as input in a data assimilation scheme in order to retrieve parameters that describe energy balance at the ground surface in the Tuscany region, in central Italy, during summer 2005. A parsimonious 1-D multiscale variational assimilation procedure has been followed, that requires also near surface meteorological observations. A simplified model of the surface energy balance that includes such assimilation scheme has been coupled with the limited area atmospheric model RAMS, in order to improve in the latter the accuracy of the energy budget at the surface. The coupling has been realized replacing the assimilation scheme products, in terms of surface turbulent fluxes and temperature and humidity states during the meteorological simulation. Comparisons between meteorological model results with and without coupling with the assimilation scheme are discussed, both in terms of reconstruction of surface variables and of vertical characterization of the lower atmosphere. In particular, the effects of the coupling on the moisture feedback between surface and atmosphere are considered and estimates of the precipitation recycling ratio are provided. The results of the coupling experiment showed improvements in the reconstruction of the surface states by the atmospheric model and considerable influence on the atmospheric dynamics.

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