scholarly journals Estimating the effect of rainfall on the surface temperature of a tropical lake

2018 ◽  
Author(s):  
Gabriel Gerard Rooney ◽  
Nicole van Lipzig ◽  
Wim Thiery
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Kinetic Energy ◽  
Surface Temperature ◽  
Surface Air Temperature ◽  
Daily Rainfall ◽  
Tropical Lake ◽  
Lake Surface ◽  
Near Surface ◽  
Potential Control

Abstract. We make use of a unique high-quality, long-term observational dataset on a tropical lake to assess the effect of rainfall on lake surface temperature. The lake in question is Lake Kivu, one of the African Great Lakes, and was selected for its remarkably uniform climate and availability of multi-year, over-lake meteorological observations. Rain may have a cooling effect on the lake surface by lowering the near-surface air temperature, by the direct rain heat flux into the lake, by mixing the lake surface layer through the flux of kinetic energy, and by convective mixing of the lake surface layer. The potential importance of the rainfall effect is discussed in terms of both heat flux and kinetic-energy flux. To estimate the rainfall effect on the mean diurnal cycle of lake surface temperature, the data are binned into categories of daily rainfall amount. They are further filtered based on comparable values of daily mean net radiation, which reduces the influence of radiative-flux differences. Our results indicate that days with heavy rainfall may experience a reduction in lake surface temperature of approximately 0.3 K by the end of the day compared to days with light-to-moderate rainfall. Overall this study highlights a new potential control on lake surface temperature, and suggests that further efforts are needed to quantify this effect in other regions and to include this process in atmospheric models.

scholarly journals Estimating the effect of rainfall on the surface temperature of a tropical lake

2018 ◽  
Vol 22 (12) ◽  
pp. 6357-6369 ◽  
Author(s):  
Gabriel Gerard Rooney ◽  
Nicole van Lipzig ◽  
Wim Thiery
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Kinetic Energy ◽  
Surface Temperature ◽  
Land Surface ◽  
Surface Air Temperature ◽  
Daily Rainfall ◽  
Tropical Lake ◽  
Lake Surface ◽  
Near Surface

Abstract. We make use of a unique high-quality, long-term observational dataset on a tropical lake to assess the effect of rainfall on lake surface temperature. The lake in question is Lake Kivu, one of the African Great Lakes, and was selected for its remarkably uniform climate and availability of multi-year over-lake meteorological observations. Rain may have a cooling effect on the lake surface by lowering the near-surface air temperature, by the direct rain heat flux into the lake, by mixing the lake surface layer through the flux of kinetic energy and by convective mixing of the lake surface layer. The potential importance of the rainfall effect is discussed in terms of both heat flux and kinetic energy flux. To estimate the rainfall effect on the mean diurnal cycle of lake surface temperature, the data are binned into categories of daily rainfall amount. They are further filtered based on comparable values of daily mean net radiation, which reduces the influence of radiative-flux differences. Our results indicate that days with heavy rainfall may experience a reduction in lake surface temperature of approximately 0.3 K by the end of the day compared to days with light to moderate rainfall. Overall this study highlights a new potential control on lake surface temperature and suggests that further efforts are needed to quantify this effect in other regions and to include this process in land surface models used for atmospheric prediction.

scholarly journals Topographic and Mixed Layer Submesoscale Currents in the Near-Surface Southwestern Tropical Pacific

2017 ◽  
Vol 47 (6) ◽  
pp. 1221-1242 ◽  
Author(s):  
Kaushik Srinivasan ◽  
James C. McWilliams ◽  
Lionel Renault ◽  
Hristina G. Hristova ◽  
Jeroen Molemaker ◽  
...  
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Kinetic Energy ◽  
Wind Stress ◽  
Mixed Layer ◽  
Surface Heat Flux ◽  
Seasonal Cycle ◽  
Surface Heat ◽  
Near Surface ◽  
Coral Sea

AbstractThe distribution and strength of submesoscale (SM) surface layer fronts and filaments generated through mixed layer baroclinic energy conversion and submesoscale coherent vortices (SCVs) generated by topographic drag are analyzed in numerical simulations of the near-surface southwestern Pacific, north of 16°S. In the Coral Sea a strong seasonal cycle in the surface heat flux leads to a winter SM “soup” consisting of baroclinic mixed layer eddies (MLEs), fronts, and filaments similar to those seen in other regions farther away from the equator. However, a strong wind stress seasonal cycle, largely in sync with the surface heat flux cycle, is also a source of SM processes. SM restratification fluxes show distinctive signatures corresponding to both surface cooling and wind stress. The winter peak in SM activity in the Coral Sea is not in phase with the summer dominance of the mesoscale eddy kinetic energy in the region, implying that local surface layer forcing effects are more important for SM generation than the nonlocal eddy deformation field. In the topographically complex Solomon and Bismarck Seas, a combination of equatorial proximity and boundary drag generates SCVs with large-vorticity Rossby numbers (Ro ~ 10). River outflows in the Bismarck and Solomon Seas make a contribution to SM generation, although they are considerably weaker than the topographic effects. Mean to eddy kinetic energy conversions implicate barotropic instability in SM topographic wakes, with the strongest values seen north of the Vitiaz Strait along the coast of Papua New Guinea.

Future Extreme Climates Projection over Huang-Huai-Hai Region of China

2014 ◽  
Vol 955-959 ◽  
pp. 3887-3892 ◽  
Author(s):  
Huang He Gu ◽  
Zhong Bo Yu ◽  
Ji Gan Wang
Keyword(s):  
Climate Changes ◽  
Climate Model ◽  
Regional Climate ◽  
Surface Air Temperature ◽  
Daily Rainfall ◽  
Heavy Rain ◽  
Near Surface ◽  
Temperature And Precipitation ◽  
Huai River ◽  
The Future

This study projects the future extreme climate changes over Huang-Huai-Hai (3H) region in China using a regional climate model (RegCM4). The RegCM4 performs well in “current” climate (1970-1999) simulations by compared with the available surface station data, focusing on near-surface air temperature and precipitation. Future climate changes are evaluated based on experiments driven by European-Hamburg general climate model (ECHAM5) in A1B future scenario (2070-2099). The results show that the annual temperature increase about 3.4 °C-4.2 °C and the annual precipitation increase about 5-15% in most of 3H region at the end of 21st century. The model predicts a generally less frost days, longer growing season, more hot days, no obvious change in heat wave duration index, larger maximum five-day rainfall, more heavy rain days, and larger daily rainfall intensity. The results indicate a higher risk of floods in the future warmer climate. In addition, the consecutive dry days in Huai River Basin will increase, indicating more serve drought and floods conditions in this region.

scholarly journals Relative Role of Turbulent and Radiative Flux on the Near-Surface Temperature in a Single-Layer Urban Canopy Model over Houston

2017 ◽  
Vol 56 (8) ◽  
pp. 2173-2187 ◽  
Author(s):  
James Brownlee ◽  
Pallav Ray ◽  
Mukul Tewari ◽  
Haochen Tan
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Single Layer ◽  
Urban Canopy ◽  
Heat Fluxes ◽  
Radiative Flux ◽  
Hydrological Processes ◽  
Urban Canopy Model ◽  
Near Surface ◽  
Canopy Model

AbstractNumerical simulations without hydrological processes tend to overestimate the near-surface temperatures over urban areas. This is presumably due to underestimation of surface latent heat flux. To test this hypothesis, the existing single-layer urban canopy model (SLUCM) within the Weather Research and Forecasting Model is evaluated over Houston, Texas. Three simulations were conducted during 24–26 August 2000. The simulations include the use of the default “BULK” urban scheme, the SLUCM without hydrological processes, and the SLUCM with hydrological processes. The results show that the BULK scheme was least accurate, and it overestimated the near-surface temperatures and winds over the urban regions. In the presence of urban hydrological processes, the SLUCM underestimates these parameters. An analysis of the surface heat fluxes suggests that the error in the BULK scheme is due to a lack of moisture at the urban surface, whereas the error in the SLUCM with hydrological processes is due to increases in moisture at the urban surface. These results confirm earlier studies in which changes in near-surface temperature were primarily due to the changes in the turbulent (latent and sensible heat) fluxes in the presence of hydrological processes. The contribution from radiative flux was about one-third of that from turbulent flux. In the absence of hydrological processes, however, the results indicate that the changes in radiative flux contribute more to the near-surface temperature changes than the turbulent heat flux. The implications of these results are discussed.

scholarly journals Near–surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

2015 ◽  
Vol 12 (8) ◽  
pp. 7665-7687 ◽  
Author(s):  
C. L. Pérez Díaz ◽  
T. Lakhankar ◽  
P. Romanov ◽  
J. Muñoz ◽  
R. Khanbilvardi ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Skin Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Hydrological Cycle ◽  
Critical Role ◽  
Surface Air Temperature ◽  
Balance Model ◽  
Near Surface

Abstract. Land Surface Temperature (LST) is a key variable (commonly studied to understand the hydrological cycle) that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air) and snow skin temperature (T-skin) helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS) LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE) for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

Recent Trends in Land Surface Temperature on the Tibetan Plateau

2006 ◽  
Vol 19 (12) ◽  
pp. 2995-3003 ◽  
Author(s):  
Yuichiro Oku ◽  
Hirohiko Ishikawa ◽  
Shigenori Haginoya ◽  
Yaoming Ma
Keyword(s):  
Tibetan Plateau ◽  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Precipitation Amount ◽  
Surface Air Temperature ◽  
The Tibetan Plateau ◽  
Near Surface ◽  
Diurnal Range

Abstract The diurnal, seasonal, and interannual variations in land surface temperature (LST) on the Tibetan Plateau from 1996 to 2002 are analyzed using the hourly LST dataset obtained by Japanese Geostationary Meteorological Satellite 5 (GMS-5) observations. Comparing LST retrieved from GMS-5 with independent precipitation amount data demonstrates the consistent and complementary relationship between them. The results indicate an increase in the LST over this period. The daily minimum has risen faster than the daily maximum, resulting in a narrowing of the diurnal range of LST. This is in agreement with the observed trends in both global and plateau near-surface air temperature. Since the near-surface air temperature is mainly controlled by LST, this result ensures a warming trend in near-surface air temperature.

Study on Urban Thermal Environment based on Diurnal Temperature Range

2020 ◽  
Author(s):  
Zheng Guo ◽  
Miaomiao Cheng
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Thermal Environment ◽  
Surface Air Temperature ◽  
Heat Island ◽  
Near Surface ◽  
Diurnal Range ◽  
Urban Thermal Environment

<p>Diurnal temperature range (includes land surface temperature diurnal range and near surface air temperature diurnal range) is an important meteorological parameter, which is a very important factor in the field of the urban thermal environmental. Nowadays, the research of urban thermal environment mainly focused on surface heat island and canopy heat island.</p><p>Based on analysis of the current status of city thermal environment. Firstly, a method was proposed to obtain near surface air temperature diurnal range in this study, difference of land surface temperature between day and night were introduced into the improved temperature vegetation index feature space based on remote sensing data. Secondly, compared with the district administrative division, we analyzed the spatial and temporal distribution characteristics of the diurnal range of land surface temperature and near surface air temperature.</p><p>The conclusions of this study are as follows:</p><p>1 During 2003-2012s, the land surface temperature and near surface air temperature diurnal range of Beijing were fluctuating upward. The rising trend of the near surface air temperature diurnal range was more significant than land surface temperature diurnal range. In addition, the rise and decline of land surface temperature and near surface air temperature diurnal range in different districts were different. In the six city districts, the land surface temperature and near surface air temperature diurnal range in the six areas of the city were mainly downward. The decline trend of near surface air temperature diurnal range was more significant than land surface temperature diurnal range.</p><p>2 During 2003-2012s, the land surface temperature and near surface air temperature diurnal range of Beijing with similar characteristics in spatial distribution, with higher distribution land surface temperature and near surface air temperature diurnal range in urban area and with lower distribution of land surface temperature and near surface air temperature diurnal range in the Northwest Mountainous area and the area of Miyun reservoir.</p>

Temperate-zone reforestation as a tool for local climate adaptation? 

2021 ◽  
Author(s):  
Kimberly Novick
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Climate Adaptation ◽  
Heat Waves ◽  
Surface Air Temperature ◽  
Climate Mitigation ◽  
Surface Cooling ◽  
Local Cooling ◽  
Near Surface ◽  
Local Climate

<p>In addition to dramatic reductions to anthropogenic greenhouse gas emissions, most pathways for limiting global warming to less than 2 degrees C rely on managed alterations to the land surface designed to increase land carbon uptake and storage (so-called “natural climate solutions”, or NCS). Reforestation is the NCS with the largest estimated climate mitigation potential, and at least in energy-limited temperate climates, evidence is mounting that transitions from short-stature ecosystems (croplands, grasslands) to forests substantially reduce surface temperature. In this way, reforestation, at least in some places, may also represent a useful tool for local climate adaptation. However, existing work on the topic has tended to focus on how reforestation affects mean annual and seasonal surface temperature, with comparatively less attention paid to the biophysical impacts of reforestation when local cooling would be most beneficial (i.e. at mid-day, and especially droughts and heat waves). Moreover, while surface temperature is a critical driver of ecosystem processes, arguably the near-surface air temperature is the more relevant target for climate adaptation. The duality between reforestation impacts on surface and air temperature has historically been challenging to deconvolve, and thus we do not yet understand the extent to which forest surface cooling extends to the air. In this talk, new strategies are discussed for blending flux tower data and remote sensing observations to uncover the links between reforestation, surface energy balance, and near-surface air temperature dynamics, with a particular emphasis on how plant water use strategies mediate these relationships during summer days and periods of hydrologic stress.  </p>

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