Surface Diurnal Temperature Range Research Articles

Temporal variations of hydrology and light transmission at two fixed observation stations in the East China Sea

The temporal variations of the hydrology and light transmission at two fixed position observation stations in the East China Sea (ECS) during February to March 1997 were analyzed. The fixed position observations were conducted at 29°28'N, 124°45'E (Station 409), the center of the PN section, and at 32°N, 126°E (Station 111), the center of the ECS Cold Eddy. The results indicate: the semidiurnal tide generated semidiurnal variations of temperature, salinity and light transmission due to horizontal advection, but the resuspension effect of the semidiurnal tide still need to be analyzed; the sea surface diurnal temperature range was as large as 0.2°C during low wind period; the resuspension due to wind disturbance at the two stations (with water depth of more than 80 m) seemed to be small; from late February to early March, the near bottom water temperature as well as light transmission at Station 111 sharply decreased.

EQUILIBRIUM EVAPORATION AND POSITWE EVAPORATION‐SURFACE TEMPERATURE RELATIONSHIPS ACROSS A GRASSLAND1

ABSTRACTSensible (H) and latent (LE) heat fluxes, soil moisture (SM) and surface temperatures (Ts) were analyzed from seven sites at FIFE to evaluate relationships among the spatial variability of evaporative fraction, EF, SM, and the diurnal surface temperature range (Tdr). Intersite correlations between EF and Tdr were significantly negative for regional average soil moisture SMr < 20 percent, insignificant for 20 < SMr < 27 percent, and slightly positive for SMr > 27 percent. Statistical analysis of the pooled correlation coefficient between EF and Tdr for SMr < 20 percent indicates that it is less than zero at a very high level of significance, while the pooled correlation coefficient for regional SMr > 27 percent is greater than zero at the 10 percent level. The positive EF:Tdr correlations are attributed to increased surface vapor pressure at warmer sites under nearly potential conditions. These results suggest that to characterize the spatial variability of the energy budget partitioning, a variable representing the thermal response of the site should be included. An important application of these findings relates to modeling the subgrid variability of a region by subdividing the region into a few classes within which surface variables and parameters are assumed invariant. The thermal response of the surface should be included as a variable in defining these classes.

Combining afternoon and morning NOAA satellites for thermal inertia estimation: 2. Methodology and application

This is the second in a series of two papers on thermal inertia estimation from satellite data. In this paper we present the methodology that permits thermal inertia mapping using NOAA‐advanced very high resolution radiometer data from the four temperatures algorithm developed in the first paper. Four NOAA images are used to assess thermal inertia: an image at 14:30 (nominal hour) is used to estimate the surface albedo; others at 2:30 and 14:30 are used to estimate the diurnal surface temperature range, while images at 7:30, 14:30, and 19:30 are used to assess the phase difference. The main advantage of the methodology is that the phase difference is obtained from satellite data without the need to know the value of the effective surface emissivity and total water vapor content of the atmosphere. Following the proposed algorithm and the developed methodology, maps of thermal inertia are presented, two for the Iberian Peninsula (on two consecutive days to check consistency of the results) and one for Morocco (to check behavior in different landscapes). The thermal inertia values obtained are consistent with the known properties of these zones.

Land-Surface Model Development for the GISS GCM

Abstract A land-surface model is linked to the Goddard Institute for Space Studies (GISS) GCM Model II to form Model II-LS. The land-surface model primarily influences the simulation of surface air temperature over land, both in monthly means and diurnal range, and affects the major components of the hydrologic cycle over land—evapotranspiration, runoff, and, more indirectly, precipitation. Comparisons of January and July results of Model II-LS to results generated from the GISS GCM Model II and to observations show that the new land surface primarily provides improvements in the simulation of global evaporation and diurnal surface temperature range. The interannual variability of June–August surface air temperature in the Northern Hemisphere is also improved. When the land-surface model is combined with new parameterizations for moist convection and the planetary boundary layer, the combined version of the GCM yields improvements in evaporation. Simulations of a grassland site from an off-line version of...

Soil‐vegetation‐atmosphere processes: Simulation and field measurement for deforested sites in northern Thailand

In recent efforts to predict the climatic impacts of tropical deforestation an extreme scenario of impoverished grassland has been used to represent the future deforested landscape. Currently, deforested areas of the tropics are composed of a mosaic of crops, bare soil, grassland, and secondary vegetation of various ages. The dominant feature of deforested land is often secondary vegetation. Parameter values for important forest replacement land covers, including secondary vegetation, have been shown to differ from those of forest much less than that assumed in general circulation model (GCM) deforestation experiments. For this study, the biosphere‐atmosphere transfer scheme (BATS) is run in uncoupled mode using measured input data in place of GCM forcing and using the same parameter settings employed in recent deforestation experiments. Model output is compared with measurements taken over seven different deforested land surfaces in northern Thailand. Comparisons reveal that the simulation of deforested land overestimates reflected shortwave radiation, the diurnal range of surface temperature for secondary vegetation, surface soil moisture loss during periods without rain, and surface soil moisture increase at the start of a rainy period and underestimates net radiation, the diurnal range of surface temperature on recently used land surfaces, and root zone soil moisture increase at the start of a rainy period at most sites. Most deforested land surfaces, especially intermediate and advanced secondary vegetation, are more similar, in terms of land surface‐atmosphere interaction, to the model simulation of forest than of deforested land as depicted in GCM experiments. These comparisons suggest that modelers aspiring to make realistic simulations of deforestation should adopt parameter settings representative of the diverse range of forest replacement land covers, instead of again using the grassland scenario.

The Influence of Variations in Surface Treatment on 24-Hour Forecasts with a Limited Area Model, Including a Comparison of Modeled and Satellite-Measured Surface Temperatures

The effect of variations in surface parameters on 24-hour limited area forecasts has been examined on a day in July 1981. The vehicle for the study is a ten-level primitive equation model covering most of the continental United States. Variations in moisture availability, surface roughness and soil flux treatment generally do not produce large differences in 24-hour forecasts of primary variables, except in the extreme cases. Precipitation totals, however, are surprisingly sensitive to the surface treatment in several areas where significant amounts of precipitation are evidenced in a control forecast. In these areas, modulations of 10–30% of the control amount due to surface changes are common. In the areas exhibiting principally large-scale precipitation, evidence points to modulations in evaporation as the cause for the precipitation differences. Areas of principally convective precipitation exhibit differences which can be attributed to model-calculated changes in low-level moisture convergence patterns between forecasts. Diurnal surface temperature range measured by the VAS instrument on GOUES-3 is compared to those generated in model experiments over the model grid. Good agreement is found in arm with moderate to large moisture availability and roughness heights. Poor agreement is evidenced in the western United States where the daytime surface temperature and flux balance is shown to be critically sensitive to small errors in the moisture availability.

A Model for Predicting Diurnal Height Variations of Quasi-Constant-Density Tetroons

Abstract A model has been developed for predicting diurnal height changes of quasi-constant-density Mylar tetroons resulting from the complex interaction between thermally induced density changes of the tetroon and height-dependent ambient diurnal density changes in the lower 600 m of the atmosphere. The effects of solar and nocturnal radiation on tetroon altitude are included in the model. These cyclic height variations would be additive to the effects of mechanical and thermal vertical air currents acting on the tetroon. The magnitudes of the height variations for flights at <300 m above ground are so large that they should be considered in flight planning to prevent premature grounding of the tetroons. A diurnal surface temperature range of 13°C (24°F) and the condition that air and tetroon temperature are always equal, gives a predicted diurnal height change of ∼250 m for tetroons deployed for flight at 300 m above the surface. By applying 8°C maximum superheating by day and 7°C supercooling by night,...

Remote Sensing of Surface Soil Moisture

The unique thermal and dielectric properties of water afford two possibilities for remotely sensing the moisture content in the surface layer of the soil. Observations of the diurnal range of surface temperature, the microwave brightness temperature (emissivity) and radar backscatter of the soil have shown correlations of up to 0.9 with the moisture in the surface layer (about 5 cm thick). The microwave techniques appear to maintain their sensitivity to moisture variations in the presence of a crop canopy. Observations of microwave brightness temperature from satellite platforms have qualitatively confirmed this sensitivity for a wide range of conditions.

Sensitivity of the Diurnal Surface Temperature Range to Changes in Physical Parameters

An analysis is made to determine the sensitivity of theoretical deductions of the diurnal temperature range to changes in 1) parameterization constants, 2) atmospheric variables, and 3) surface-state variables. It is found, at four locations of differing latitude, that the diurnal temperature range deduced from the model is relatively insensitive to changes in the parameterization constants, a necessary condition for the validity of the model. Of the two remaining groups of variables, it is found that changes in cloud cover and in the surface-state variables albedo and conductive capacity induce the largest temperature range changes on a percentage basis. The implications of these results for the effects of vegetation changes are discussed, with special reference to the Sinai-Negev-Nile region.

Micro-meteorological study on the effect of straw-matting

In this paper, we studied the effect of straw-matting in the winter season.On the comparing with the case of being covered with straw-matting all the day long and the case of being uncovered in day time, as shown Fig. 1, it was made clear that in the latter the minimum ground surface temperature is higher shout 2°C on the mean and 5.8°C on the maximum than the former.Then, it is very convinient, if we know that in the case of covering straw-matting, how much thick of straw-matting is desirable for the certain cold.When the surface temperature of straw-matting is y and its amplitude A, if it is assumed that there is such a relationship as y=A sin nt, the diurnal change of the temperature at Xcm depth, is shown as following formula.Y=Ae-X/K√n/2sin(nt-X/K√n/2)When the diurnal range of the temperature at Xcm depth is placed to R, it isR=2Ae-X/K√n/2The formula is transformed as following.X/K√n/2loge=log2A-logROn the straw-matting of 11cm thick and of 18cm thick, being calculated (log2A-logR) respectively and counted K from those values, K is about 0.045.Therefore, the following formula is obtained.X=17(log2A-logR)There are close relations between the diurnal range of the surface temperature of the straw-matting (2A) with the diurnal range of the surface temperature at the uncovered ground, and the diurnal rang of the ground surface temperature under the straw-matting with the minimum ground surface temperature under the straw-matting.From the above relations, in order to know that, when the diurnal range of the uncovered ground surface temperature is obtained, how much thick of straw-matting are desirable that the temperature under the straw matting might not lower less than the certain temperture, the figure such as Fig. 2 was tried to make.