The Role of Northern Lakes in a Regional Energy Balance

2005 ◽  
Vol 6 (3) ◽  
pp. 291-305 ◽  
Author(s):  
Wayne R. Rouse ◽  
Claire J. Oswald ◽  
Jacqueline Binyamin ◽  
Christopher Spence ◽  
William M. Schertzer ◽  
...  
Keyword(s):  
Surface Energy ◽  
Heat Storage ◽  
Regional Climate ◽  
Heat Fluxes ◽  
Net Radiation ◽  
Large Lakes ◽  
Regional Energy ◽  
Energy Balances ◽  
Lake Size

Abstract There are many lakes of widely varying morphometry in northern latitudes. For this study region, in the central Mackenzie River valley of western Canada, lakes make up 37% of the landscape. The nonlake components of the landscape are divided into uplands (55%) and wetlands (8%). With such abundance, lakes are important features that can influence the regional climate. This paper examines the role of lakes in the regional surface energy and water balance and evaluates the links to the frequency–size distribution of lakes. The primary purpose is to examine how the surface energy balance may influence regional climate and weather. Lakes are characterized by both the magnitude and temporal behavior of their surface energy balances during the ice-free period. The impacts of combinations of various-size lakes and land–lake distributions on regional energy balances and evaporation cycles are presented. Net radiation is substantially greater over all water-dominated surfaces compared with uplands. The seasonal heat storage increases with lake size. Medium and large lakes are slow to warm in summer. Their large cumulative heat storage, near summer’s end, fuels large convective heat fluxes in fall and early winter. The evaporation season for upland, wetland, and small, medium, and large lakes lasts for 19, 21, 22, 24, and 30 weeks, respectively. The regional effects of combinations of surface types are derived. The region is initially treated as comprising uplands only. The influences of wetland, small, medium, and large lakes are added sequentially, to build up to the energy budget of the actual landscape. The addition of lakes increases the regional net radiation, the maximum regional subsurface heat storage, and evaporation substantially. Evaporation decreases slightly in the first half of the season but experiences a large enhancement in the second half. The sensible heat flux is reduced substantially in the first half of the season, but changes little in the second half. For energy budget modeling the representation of lake size is important. Net radiation is fairly independent of size. An equal area of medium and large lakes, compared with small lakes, yields substantially larger latent heat fluxes and lesser sensible heat fluxes. Lake size also creates large differences in regional flux magnitudes, especially in the spring and fall periods.

scholarly journals Soil Moisture–Atmosphere Interactions during the 2003 European Summer Heat Wave

2007 ◽  
Vol 20 (20) ◽  
pp. 5081-5099 ◽  
Author(s):  
E. M. Fischer ◽  
S. I. Seneviratne ◽  
P. L. Vidale ◽  
D. Lüthi ◽  
C. Schär
Keyword(s):  
Soil Moisture ◽  
Heat Wave ◽  
Regional Climate ◽  
Heat Fluxes ◽  
Sensible Heat ◽  
Net Radiation ◽  
Temperature Anomalies ◽  
Continental Scale ◽  
Summer Heat

Abstract The role of land surface–related processes and feedbacks during the record-breaking 2003 European summer heat wave is explored with a regional climate model. All simulations are driven by lateral boundary conditions and sea surface temperatures from the ECMWF operational analysis and 40-yr ECMWF Re-Analysis (ERA-40), thereby prescribing the large-scale circulation. In particular, the contribution of soil moisture anomalies and their interactions with the atmosphere through latent and sensible heat fluxes is investigated. Sensitivity experiments are performed by perturbing spring soil moisture in order to determine its influence on the formation of the heat wave. A multiyear regional climate simulation for 1970–2000 using a fixed model setup is used as the reference period. A large precipitation deficit together with early vegetation green-up and strong positive radiative anomalies in the months preceding the extreme summer event contributed to an early and rapid loss of soil moisture, which exceeded the multiyear average by far. The exceptionally high temperature anomalies, most pronounced in June and August 2003, were initiated by persistent anticyclonic circulation anomalies that enabled a dominance of the local heat balance. In this experiment the hottest phase in early August is realistically simulated despite the absence of an anomaly in total surface net radiation. This indicates an important role of the partitioning of net radiation in latent and sensible heat fluxes, which is to a large extent controlled by soil moisture. The lack of soil moisture strongly reduced latent cooling and thereby amplified the surface temperature anomalies. The evaluation of the experiments with perturbed spring soil moisture shows that this quantity is an important parameter for the evolution of European heat waves. Simulations indicate that without soil moisture anomalies the summer heat anomalies could have been reduced by around 40% in some regions. Moreover, drought conditions are revealed to influence the tropospheric circulation by producing a surface heat low and enhanced ridging in the midtroposphere. This suggests a positive feedback mechanism between soil moisture, continental-scale circulation, and temperature.

scholarly journals Water tracks intensify surface energy and mass exchange in the Antarctic McMurdo Dry Valleys

2019 ◽  
Vol 13 (8) ◽  
pp. 2203-2219 ◽  
Author(s):  
Tobias Linhardt ◽  
Joseph S. Levy ◽  
Christoph K. Thomas
Keyword(s):  
Climate Change ◽  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Heat Fluxes ◽  
Dry Valleys ◽  
Sensible Heat ◽  
Net Radiation ◽  
Taylor Valley ◽  
The Antarctic

Abstract. The hydrologic cycle in the Antarctic McMurdo Dry Valleys (MDV) is mainly controlled by surface energy balance. Water tracks are channel-shaped high-moisture zones in the active layer of permafrost soils and are important solute and water pathways in the MDV. We evaluated the hypothesis that water tracks alter the surface energy balance in this dry, cold, and ice-sheet-free environment during summer warming and may therefore be an increasingly important hydrologic feature in the MDV in the face of landscape response to climate change. The surface energy balance was measured for one water track and two off-track reference locations in Taylor Valley over 26 d of the Antarctic summer of 2012–2013. Turbulent atmospheric fluxes of sensible heat and evaporation were observed using the eddy-covariance method in combination with flux footprint modeling, which was the first application of this technique in the MDV. Soil heat fluxes were analyzed by measuring the heat storage change in the thawed layer and approximating soil heat flux at ice table depth by surface energy balance residuals. For both water track and reference locations over 50 % of net radiation was transferred to sensible heat exchange, about 30 % to melting of the seasonally thawed layer, and the remainder to evaporation. The net energy flux in the thawed layer was zero. For the water track location, evaporation was increased by a factor of 3.0 relative to the reference locations, ground heat fluxes by 1.4, and net radiation by 1.1, while sensible heat fluxes were reduced down to 0.7. Expecting a positive snow and ground ice melt response to climate change in the MDV, we entertained a realistic climate change response scenario in which a doubling of the land cover fraction of water tracks increases the evaporation from soil surfaces in lower Taylor Valley in summer by 6 % to 0.36 mm d−1. Possible climate change pathways leading to this change in landscape are discussed. Considering our results, an expansion of water track area would make new soil habitats accessible, alter soil habitat suitability, and possibly increase biological activity in the MDV. In summary, we show that the surface energy balance of water tracks distinctly differs from that of the dominant dry soils in polar deserts. With an expected increase in area covered by water tracks, our findings have implications for hydrology and soil ecosystems across terrestrial Antarctica.

scholarly journals The surface energy balance of a polygonal tundra site in northern Siberia – Part 1: Spring to fall

2011 ◽  
Vol 5 (1) ◽  
pp. 151-171 ◽  
Author(s):  
M. Langer ◽  
S. Westermann ◽  
S. Muster ◽  
K. Piel ◽  
J. Boike
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Surface Energy ◽  
Snow Cover ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Surface Energy Balance ◽  
Heat Fluxes ◽  
Net Radiation ◽  
Ground Heat Flux

Abstract. In this article, we present a study on the surface energy balance of a polygonal tundra landscape in northeast Siberia. The study was performed during half-year periods from April to September in each of 2007 and 2008. The surface energy balance is obtained from independent measurements of the net radiation, the turbulent heat fluxes, and the ground heat flux at several sites. Short-wave radiation is the dominant factor controlling the magnitude of all the other components of the surface energy balance during the entire observation period. About 50% of the available net radiation is consumed by the latent heat flux, while the sensible and the ground heat flux are each around 20 to 30%. The ground heat flux is mainly consumed by active layer thawing. About 60% of the energy storage in the ground is attributed to the phase change of soil water. The remainder is used for soil warming down to a depth of 15 m. In particular, the controlling factors for the surface energy partitioning are snow cover, cloud cover, and the temperature gradient in the soil. The thin snow cover melts within a few days, during which the equivalent of about 20% of the snow-water evaporates or sublimates. Surface temperature differences of the heterogeneous landscape indicate spatial variabilities of sensible and latent heat fluxes, which are verified by measurements. However, spatial differences in the partitioning between sensible and latent heat flux are only measured during conditions of high radiative forcing, which only occur occasionally.

scholarly journals Lake and climate models linkage: a 3-D hydrodynamic contribution

2005 ◽  
Vol 4 ◽  
pp. 57-62 ◽  
Author(s):  
L. F. Leon ◽  
D. Lam ◽  
W. Schertzer ◽  
D. Swayne
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Heat Fluxes ◽  
Large Lakes ◽  
Atmospheric Sciences ◽  
Lake Model ◽  
Realistic Representation ◽  
Heat Exchanges

Abstract. Under a Canadian Foundation for Climate and Atmospheric Sciences (CFCAS) project, targeted to study the feasibility to link regional climate models with lake models, one of the tasks was to consider such a coupling in large lakes. The objective is to provide detailed information on temperature and circulation distributions of the lake to take into account the spatial variability for temperature and the heat exchange through the water's surface. The major contribution of this work is focused on realistic representation of the heat fluxes and temperature distributions to and from lakes especially during the thermally stratified ice-free periods. This paper presents the detailed 3-D ELCOM model applied in Lake Erie in order to produce, at the surface layer of the lake, the spatial distribution of temperature and heat exchanges that eventually can be coupled with a regional climate model (CRCM). Preliminary results will be presented on how this lake model may improve the regional climate models, which currently do not consider such large lake circulation effects.

Blowin’ in the wind: reciprocal airborne carbon fluxes between lakes and land This paper is based on the J.C. Stevenson Memorial Lecture presented at the Canadian Conference for Fisheries Research (CCFFR) in Ottawa, Ontario, 9–11 January 2009.

2011 ◽  
Vol 68 (1) ◽  
pp. 170-182 ◽  
Author(s):  
M. Jake Vander Zanden ◽  
Claudio Gratton
Keyword(s):  
Carbon Flux ◽  
Open Water ◽  
Memorial Lecture ◽  
Published Data ◽  
Insect Emergence ◽  
Large Lakes ◽  
Lake Ecosystems ◽  
Ecosystem Size ◽  
Lake Size

Ecologists are increasingly interested in how disjunct habitats are connected through the cross-habitat movement of matter, prey, nutrients, and detritus and the implications for recipient systems. The study of lake ecosystems has been dominated by the study of pelagic (open-water) production and processes, though there is growing awareness of the role of terrestrial inputs and benthic trophic pathways. Here, we review the phenomena of airborne fluxes to and from lakes. We assemble published data on terrestrial particulate organic carbon (TPOC) deposition to lakes, insect production, and insect emergence and use these data to simulate how airborne lake-to-land and land-to-lake carbon flux is expected to scale with ecosystem size, while taking into account among-lake variability in emergence and TPOC deposition. Emergent insect flux to land increases as a function of lake size, while TPOC deposition to lakes decreases as a function of lake size. TPOC deposition exceeds insect emergence in small lakes, while in large lakes, insect emergence exceeds TPOC deposition. We present a general framework for considering directional fluxes across habitat boundaries. Furthermore, our results highlight the overarching role of ecosystem geometry in determining insect emergence, airborne carbon deposition, and net carbon flux between adjacent ecosystems.

scholarly journals Urban Energy Balance Obtained from the Comprehensive Outdoor Scale Model Experiment. Part I: Basic Features of the Surface Energy Balance

2010 ◽  
Vol 49 (7) ◽  
pp. 1341-1359 ◽  
Author(s):  
Toru Kawai ◽  
Manabu Kanda
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Heat Storage ◽  
Heat Fluxes ◽  
Eddy Correlation ◽  
Scale Model ◽  
Surface Geometry ◽  
Urban Energy Balance ◽  
Basic Features

Abstract The objective of this study is to examine the basic features of the surface energy balance (SEB) using the data obtained from the Comprehensive Outdoor Scale Model (COSMO). COSMO is an idealized miniature city that has no vegetation, no human activity, and no heterogeneity of the surface geometry. The basic features of the SEB such as energy balance closure, the ensemble mean of the diurnal variation of the energy balance, and the daytime and daily statistics of the energy balance were investigated. The following were the main findings of the study: 1) A surface energy imbalance was observed. The sum of sensible and latent heat fluxes estimated by the eddy correlation method underestimated the available energy by 1% during the daytime and by 44% during the night. 2) Large heat storage in the daytime and small radiative cooling at night sustained positive sensible heat fluxes throughout the night in all seasons and in all sunshine conditions. 3) The daytime ratio of heat storage ΔQS to net radiation Q*, ΔQS/Q*, depended on the friction velocity u* and decreased with increasing u*. 4) The values of ΔQS/Q* tended to be larger in winter than in summer. The annual averaged value of this ratio was approximately 0.6. 5) The large volumetric heat capacity of the surface materials and the resulting large energetic hysteresis produced nonzero total daily values of heat storage. The total daily values of heat storage largely depended on the weather (i.e., sunshine condition and with or without rainfall) and showed positive and negative values on clear-sky days and rainy days, respectively.

Northern Lake Impacts on Local Seasonal Climate

2007 ◽  
Vol 8 (4) ◽  
pp. 881-896 ◽  
Author(s):  
Z. Long ◽  
W. Perrie ◽  
J. Gyakum ◽  
D. Caya ◽  
R. Laprise
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Ocean Model ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Good Representation ◽  
Large Lakes ◽  
Seasonal Climate ◽  
Surface Heat Fluxes ◽  
Local Water

Abstract It is well known that large lakes can perturb local weather and climate through mesoscale circulations, for example, lake effects on storms and lake breezes, and the impacts on fluxes of heat, moisture, and momentum. However, for both large and small lakes, the importance of atmosphere–lake interactions in northern Canada is largely unknown. Here, the Canadian Regional Climate Model (CRCM) is used to simulate seasonal time scales for the Mackenzie River basin and northwest region of Canada, coupled to simulations of Great Bear and Great Slave Lakes using the Princeton Ocean Model (POM) to examine the interactions between large northern lakes and the atmosphere. The authors consider the lake impacts on the local water and energy cycles and on regional seasonal climate. Verification of model results is achieved with atmospheric sounding and surface flux data collected during the Canadian Global Energy and Water Cycle Experiment (GEWEX) program. The coupled atmosphere–lake model is shown to be able to successfully simulate the variation of surface heat fluxes and surface water temperatures and to give a good representation of the vertical profiles of water temperatures, the warming and cooling processes, and the lake responses to the seasonal and interannual variation of surface heat fluxes. These northern lakes can significantly influence the local water and energy cycles.

scholarly journals The response of tropical precipitation to Earth's precession: The role of fluxes and vertical stability

2018 ◽  
Author(s):  
Chetankumar Jalihal ◽  
Joyce Helena Catharina Bosmans ◽  
Jayaraman Srinivasan ◽  
Arindam Chakraborty
Keyword(s):  
Surface Energy ◽  
Bay Of Bengal ◽  
Heat Fluxes ◽  
Energy Fluxes ◽  
Surface Energy Fluxes ◽  
Tropical Precipitation ◽  
Vertical Stability ◽  
Stability Change ◽  
The Tropics

Abstract. The changes in Earth's precession have an impact on tropical precipitation. These changes have been ascribed to the changes in solar radiation at the top of the atmosphere, but this cannot explain the variations in precipitation over oceans. Using energy and moisture budget equations we have shown that the surface energy fluxes, as well as vertical stability, have to be taken into consideration along with insolation, to explain these changes in precipitation. Energy fluxes explain most of the changes in precipitation, when looking at the mean response over the tropics. However, there are regions like the Arabian sea and Africa where stability change is the main cause of change in precipitation. Hence, insolation cannot be thought of as the sole driver of precipitation on orbital timescales, but surface energy and vertical stability should also be considered when looking at oceans or smaller land regions. The decrease in precipitation over the Bay of Bengal, with higher summer insolation, has been shown to be due to the decrease in surface latent heat fluxes. This is a consequence of the remote response of the atmosphere to the enhanced latent heating to the west of Bay of Bengal. This leads to a decrease in wind speed over the Bay of Bengal and hence reduces the total column energy available for convection.

scholarly journals Sensitivity of Convection-Permitting Regional Climate Simulations to Changes in Land Cover Input Data: Role of Land Surface Characteristics for Temperature and Climate Extremes

2021 ◽  
Vol 9 ◽  
Author(s):  
Merja H. Tölle ◽  
Evgenii Churiulin
Keyword(s):  
Land Cover ◽  
Urban Areas ◽  
Input Data ◽  
Regional Climate ◽  
Surface Characteristics ◽  
Heat Fluxes ◽  
Area Index ◽  
Land Cover Types ◽  
Land Cover Maps

Characterization of climate uncertainties due to different land cover maps in regional climate models is essential for adaptation strategies. The spatiotemporal heterogeneity in surface characteristics is considered to play a key role in terrestrial surface processes. Here, we quantified the sensitivity of model results to changes in land cover input data (GlobCover 2009, GLC 2000, CCI, and ECOCLIMAP) in the regional climate model (RCM) COSMO-CLM (v5.0_clm16). We investigated land cover changes due to the retrieval year, number, fraction and spatial distribution of land cover classes by performing convection-permitting simulations driven by ERA5 reanalysis data over Germany from 2002 to 2011. The role of the surface parameters on the surface turbulent fluxes and temperature is examined, which is related to the land cover classes. The bias of the annual temperature cycle of all the simulations compared with observations is larger than the differences between simulations. The latter is well within the uncertainty of the observations. The land cover class fractional differences are small among the land cover maps. However, some land cover types, such as croplands and urban areas, have greatly changed over the years. These distribution changes can be seen in the temperature differences. Simulations based on the CCI retrieved in 2000 and 2015 revealed no accreditable difference in the climate variables as the land cover changes that occurred between these years are marginal, and thus, the influence is small over Germany. Increasing the land cover types as in ECOCLIMAP leads to higher temperature variability. The largest differences among the simulations occur in maximum temperature and from spring to autumn, which is the main vegetation period. The temperature differences seen among the simulations relate to changes in the leaf area index, plant coverage, roughness length, latent and sensible heat fluxes due to differences in land cover types. The vegetation fraction was the main parameter affecting the seasonal evolution of the latent heat fluxes based on linear regression analysis, followed by roughness length and leaf area index. If the same natural vegetation (e.g. forest) or pasture grid cells changed into urban types in another land cover map, daily maximum temperatures increased accordingly. Similarly, differences in climate extreme indices are strongest for any land cover type change to urban areas. The uncertainties in regional temperature due to different land cover datasets were overall lower than the uncertainties associated with climate projections. Although the impact and their implications are different on different spatial and temporal scales as shown for urban area differences in the land cover maps. For future development, more attention should be given to land cover classification in complex areas, including more land cover types or single vegetation species and regional representative classification sample selection. Including more sophisticated urban and vegetation modules with synchronized input data in RCMs would improve the underestimation of the urban and vegetation effect on local climate.

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