Review: Estimation of surface energy fluxes in the Arctic tundra

2016 ◽  
Author(s):  
Anonymous
Keyword(s):  
Surface Energy ◽  
Arctic Tundra ◽  
The Arctic ◽  
Energy Fluxes ◽  
Surface Energy Fluxes

Interannual Variability in Arctic Surface Energy Fluxes and their Drivers

2021 ◽  
Author(s):  
Raleigh Grysko ◽  
Jacqueline Oehri ◽  
Gabriela Schaepman-Strub
Keyword(s):  
Surface Energy ◽  
Interannual Variability ◽  
Energy Budget ◽  
Climate Warming ◽  
Atmospheric Stability ◽  
Surface Energy Budget ◽  
The Arctic ◽  
Energy Fluxes ◽  
Surface Energy Fluxes ◽  
Arctic Surface

<div> <p>The Arctic is undergoing amplified climate warming, and temperature and precipitation are predicted to increase even more in the future. Increased climate warming is indicative of changes in the surface energy budget, which lies at the heart of the carbon and water budget. The surface energy budget is an important driver of many earth system processes, and yet has received little attention in the past.</p> </div><div> <p>The goal of this study is to further develop our understanding in the spatio-temporal variability of Arctic surface energy fluxes. Specifically, we will investigate the magnitude and dependence on changes in energy flux drivers interannually at different sites across the Arctic. We used<span> </span><em>in situ</em><span> </span>data from 10 sites gathered from the FLUXNET2015, Arctic Observatory Network, and European Fluxes Database Center repositories. All study sites are of 60° N or higher and spread across the Arctic. The chosen sites include Chokurdakh, Russia (147.5° E, 70.8° N), Cherskiy, Russia (161.3° E, 68.6° N), Kaamanen,, Finland (27.3° E, 69.1° N), Imnavait Creek, USA (-149.3° E, 68.6° N), Zackenberg Heath, Greenland (-20.6° E, 74.5° N), Tiksi, Russia (128.9° E, 71.6° N), Sodankyla, Finland (26.6° E, 67.4° N), Poker Flat, USA (-147.5° E, 65.1° N), Nuuk, Greenland (-51.4° E, 64.1° N), and Samoylov, Russia (126.5° E, 72.4° N). Using these data, we analyzed the interannual variability of surface energy fluxes including net radiation, sensible, latent, and ground heat fluxes, and Bowen ratio including their dependence on potential drivers, such as temperature, wind speed, atmospheric stability, and vapor pressure deficit.</p> </div><p>Our results on interannual variability in surface energy fluxes and flux drivers inform long term climate model simulations across the Arctic, which is critical for the improved prediction of the state and development of the surface energy budget and drivers under current and future conditions in this vulnerable, rapidly changing, and understudied region.</p>

Evaluation of land-atmosphere processes of the Polar WRF in the summertime Arctic tundra

2020 ◽  
Author(s):  
Jeongwon Kim ◽  
Junhong Lee ◽  
Je-Woo Hong ◽  
Jinkyu Hong ◽  
Ja-Ho Koo ◽  
...  
Keyword(s):  
Surface Energy ◽  
Polar Region ◽  
Climate Model ◽  
Regional Climate ◽  
Arctic Tundra ◽  
The Arctic ◽  
Weather Research And Forecasting ◽  
Physical Parameters ◽  
Observation Data ◽  
Surface Energy Fluxes

<p>Arctic tundra is changing rapidly under the influence of global warming and it is important to know its impact on local and regional climate. Polar Weather Research and Forecasting (PWRF) model is a regional climate model optimized for the polar region and it is a useful tool for studying the Arctic tundra in high resolution. In this study, we evaluate the performance of the PWRF model over the Arctic tundra on clear summer days, when the transition is taking place the most, based on the surface energy fluxes and PBL observations in Cambridge Bay, Nunavut, Canada.</p><p>The PWRF simulates a drier and warmer environment in PBL than the observations. Our analysis shows that it is due to the surface energy imbalance in the model caused by the uncertainties in prescribed initial input data and physical parameters rather than structural flaws in the model physics. The performance of the PWRF model over the Arctic tundra is improved when those values are modified based on the observation data.</p>

scholarly journals Comparison of FASST and SNTHERM in Three Snow Accumulation Regimes

2008 ◽  
Vol 9 (6) ◽  
pp. 1443-1463 ◽  
Author(s):  
Susan Frankenstein ◽  
Anne Sawyer ◽  
Julie Koeberle
Keyword(s):  
Surface Energy ◽  
Single Layer ◽  
Soil Strength ◽  
Snow Accumulation ◽  
Dynamic State ◽  
Energy Fluxes ◽  
One Dimensional ◽  
Surface Energy Fluxes ◽  
Snow Model ◽  
Surface Ice

Abstract Numerical experiments of snow accumulation and depletion were carried out as well as surface energy fluxes over four Cold Land Processes Experiment (CLPX) sites in Colorado using the Snow Thermal model (SNTHERM) and the Fast All-Season Soil Strength model (FASST). SNTHERM is a multilayer snow model developed to describe changes in snow properties as a function of depth and time, using a one-dimensional mass and energy balance. The model is intended for seasonal snow covers and addresses conditions found throughout the winter, from initial ground freezing in the fall to snow ablation in the spring. It has been used by many researchers over a variety of terrains. FASST is a newly developed one-dimensional dynamic state-of-the-ground model. It calculates the ground’s moisture content, ice content, temperature, and freeze–thaw profiles as well as soil strength and surface ice and snow accumulation/depletion. Because FASST is newer and not as well known, the authors wanted to determine its use as a snow model by comparing it with SNTHERM, one of the most established snow models available. It is demonstrated that even though FASST is only a single-layer snow model, the RMSE snow depth compared very favorably against SNTHERM, often performing better during the accumulation phase. The surface energy fluxes calculated by the two models were also compared and were found to be similar.

scholarly journals Simulated Sensitivity of Tropical Cyclone Size and Structure to the Atmospheric Temperature Profile

2016 ◽  
Vol 73 (11) ◽  
pp. 4553-4571 ◽  
Author(s):  
Diana R. Stovern ◽  
Elizabeth A. Ritchie
Keyword(s):  
Tropical Cyclone ◽  
Surface Energy ◽  
Temperature Profile ◽  
Convective Available Potential Energy ◽  
Atmospheric Temperature ◽  
Outer Core ◽  
Specific Humidity ◽  
Energy Fluxes ◽  
Surface Energy Fluxes ◽  
Size And Structure

Abstract This study uses the WRF ARW to investigate how different atmospheric temperature environments impact the size and structure development of a simulated tropical cyclone (TC). In each simulation, the entire vertical virtual temperature profile is either warmed or cooled in 1°C increments from an initial specified state while the initial relative humidity profile and sea surface temperature are held constant. This alters the initial amount of convective available potential energy (CAPE), specific humidity, and air–sea temperature difference such that, when the simulated atmosphere is cooled (warmed), the initial specific humidity and CAPE decrease (increase), but the surface energy fluxes from the ocean increase (decrease). It is found that the TCs that form in an initially cooler environment develop larger wind and precipitation fields with more active outer-core rainband formation. Consistent with previous studies, outer-core rainband formation is associated with high surface energy fluxes, which leads to increases in the outer-core wind field. A larger convective field develops despite initializing in a low CAPE environment, and the dynamics are linked to a wider field of surface radial inflow. As the TC matures and radial inflow expands, large imports of relative angular momentum in the boundary layer continue to drive expansion of the TC’s overall size.

scholarly journals Using a thermal-based two source energy balance model with time-differencing to estimate surface energy fluxes with day–night MODIS observations

2013 ◽  
Vol 17 (7) ◽  
pp. 2809-2825 ◽  
Author(s):  
R. Guzinski ◽  
M. C. Anderson ◽  
W. P. Kustas ◽  
H. Nieto ◽  
I. Sandholt
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
The United States ◽  
Surface Fluxes ◽  
Diurnal Changes ◽  
Energy Fluxes ◽  
Surface Energy Fluxes ◽  
Vegetation Fraction ◽  
Geostationary Satellites ◽  
Green Vegetation

Abstract. The Dual Temperature Difference (DTD) model, introduced by Norman et al. (2000), uses a two source energy balance modelling scheme driven by remotely sensed observations of diurnal changes in land surface temperature (LST) to estimate surface energy fluxes. By using a time-differential temperature measurement as input, the approach reduces model sensitivity to errors in absolute temperature retrieval. The original formulation of the DTD required an early morning LST observation (approximately 1 h after sunrise) when surface fluxes are minimal, limiting application to data provided by geostationary satellites at sub-hourly temporal resolution. The DTD model has been applied primarily during the active growth phase of agricultural crops and rangeland vegetation grasses, and has not been rigorously evaluated during senescence or in forested ecosystems. In this paper we present modifications to the DTD model that enable applications using thermal observations from polar orbiting satellites, such as Terra and Aqua, with day and night overpass times over the area of interest. This allows the application of the DTD model in high latitude regions where large viewing angles preclude the use of geostationary satellites, and also exploits the higher spatial resolution provided by polar orbiting satellites. A method for estimating nocturnal surface fluxes and a scheme for estimating the fraction of green vegetation are developed and evaluated. Modification for green vegetation fraction leads to significantly improved estimation of the heat fluxes from the vegetation canopy during senescence and in forests. When the modified DTD model is run with LST measurements acquired with the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra and Aqua satellites, generally satisfactory agreement with field measurements is obtained for a number of ecosystems in Denmark and the United States. Finally, regional maps of energy fluxes are produced for the Danish Hydrological ObsErvatory (HOBE) in western Denmark, indicating realistic patterns based on land use.

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