Meteorological Data Temperature Research Articles

Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes

Great Basin bristlecone pine (Pinus longaeva) at 3 sites in western North America near the upper elevation limit of tree growth showed ring growth in the second half of the 20th century that was greater than during any other 50-year period in the last 3,700 years. The accelerated growth is suggestive of an environmental change unprecedented in millennia. The high growth is not overestimated because of standardization techniques, and it is unlikely that it is a result of a change in tree growth form or that it is predominantly caused by CO(2) fertilization. The growth surge has occurred only in a limited elevational band within approximately 150 m of upper treeline, regardless of treeline elevation. Both an independent proxy record of temperature and high-elevation meteorological temperature data are positively and significantly correlated with upper-treeline ring width both before and during the high-growth interval. Increasing temperature at high elevations is likely a prominent factor in the modern unprecedented level of growth for Pinus longaeva at these sites.

Climatic effects on Salmonella survival in plant and soil irrigated with artificially inoculated wastewater: preliminary results

The use of wastewater to replace other water resources for irrigation is highly dependent on whether the health risk and environmental impacts entailed are acceptable or not. Total count and species of microorganisms found in wastewater vary widely because of climatic conditions, season, population sanitary habits and disease incidence. Salmonella, one of the genera associated with waterborne diseases, lives in the intestine. Thus, it is widely accepted that they have a limited survival period under environmental conditions. Wastewater management practices and the ability of Salmonella to survival under field conditions would determine the health risk associated with its presence in wastewater. Although chlorination is widely used, there are situations in which Salmonella is able to survive the sudden stress imposed by this technique. The aim of this experiment was to contribute to the study of the climatic and soil effects on pathogen survival under agricultural field conditions in order to assess which were the best wastewater management practices from both health and economic points of view. Five pots filled with soil seeded with Medicago sativa and an automatic weather station were used. A secondary effluent was artificially inoculated with Salmonella. In addition, open plates (filled with sterilised soil) and ultraviolet radiation isolated plates (filled with non-sterilised soil) were used. As soil heat emission contributes to the environmental conditions around the bacteria, standardised meteorological temperature data had to be carefully used in the bacterial survival studies under agricultural conditions. Radiation was the main cause of Salmonella mortality as its effect was more important than natural soil bacteria competence. Higher reduction of Salmonella counts could have been associated with longer spring days. Soil was able to effectively remove Salmonella. Subsurface drip irrigation methods could provide an effective tool to prevent health risk associated with wastewater irrigation.

Distributed Hydrological Model for Fuji River Basin

A distributed hydrological model is developed and applied to the Fuji River basin of 3,432 km2 in Japan, which is divided into squared meshes of 1-km resolution. Mesh meteorological data of temperature, wind speed, sunshine, precipitation, cloud amount, and humidity are produced from weather stations and geographic information system data by a stepwise regression method that characterizes relationships between meteorology and geography. This method provides spatially allocated daily input data. Then a comparatively simple distributed model is proposed, with a submodel of soil-vegetation-atmosphere-transfer type for any mesh and a conceptual submodel for river routing. Spatial distribution patterns and mesh-specific values of model parameters are calibrated with a geographic information system database and 3 years of meteorologic-hydrologic observations. The daily run model can simulate approximately daily processes of snow accumulation and melting, interception, evapotranspiration, and runoff components, ...

植生地における熱収支モデルおよび水田地帯への適用

A new canopy model having a simple parameter is here presented for estimating the diurnal or seasonal variations of the heat balance, employing meteorological data of temperature, wind, humidity, precipitation, and solar radiation gathered by AMeDAS near the experimental field. The calculated results were compared with observations over the rice paddy field for the two-year period of 1993 and 1994. Simulations using the presently developed canopy model agreed well with the daily-mean observed values. The rms error in the daily mean values between the observed and calculated values of surface temperature, sensible heat flux, and latent heat flux were 1.7°C, ±13 Wm -2 , and ±16 Wm -2 , respectively, during the overall observational period. The annual evapotranspiration was evaluated as about 600 mmy -1 . This value is found between the values for shallow water (564 mmy -1 ) and forests (692 mmy -1 ). The ratio of rainfall interception to evapotranspiration during the vegetated periods are about 18 % and 9 % for the year 1993 (cool summer) and 1994 (hot summer), respectively. The precipitation amount in 1993 is large, while evapotranspiration from the vegetation is small, resulting in a large rate of rainfall interception.

Studies on the screwworm flyCochliomyia hominivorax in Libya: Effect of temperature on pupation and eclosion

The American screwworm fly Cochliomyia hominivorax has recently been reported in Libya (El-Azazy 1989). Fly larvae were cultured on blood agar at different temperatures (-5 degrees, 5 degrees, 18 degrees, 20 degrees, 30 degrees, 37 degrees, or 40 degrees C). Larvae pupated at 18 degrees, 20 degrees, 30 degrees, or 37 degrees C, and the highest pupation (100%) occurred at 20 degrees C. Adult flies emerged from pupae that were maintained at 18 degrees, 20 degrees, 30 degrees, or 37 degrees C; the maximal eclosion (94%) occurred at 20 degrees C. Correlation of these findings with meteorological temperature data from local areas in which C. hominivorax myiasis occurs suggests a crucial role for temperature in the determination of the effective environment for this fly species.

A Study on Radiative Damping of Planetary Waves Utilizing Stratospheric Observations

Satellite ozone observations made by the Stratospheric Aerosol and Gas Experiment (SAGE) and corresponding meteorological temperature data are used to study the radiative damping processes associated with planetary waves during stratospheric warmings. Ramanathan's model has been adapted for the radiative heating and cooling calculations. The derived infrared damping coefficients, based on observed stratospheric ozone and temperature, are compared with the Newtonian cooling coefficients of Dickinson and Fels. It is also shown that the negative correlation between temperature and ozone solar heating in the upper stratosphere accelerates the damping rate due to infrared cooling alone, in agreement with the theoretical analysis and an earlier report based on observations. In addition, it is also found in this analysis that the phase relationship between ozone and solar heating waves is characterized by its behavior in three distinct layers. In the regions above about 2 mb and also below about 10 mb, the waves are closely in-phase. Between approximately 2 and 10 mb, they show a departure from the in-phase relationship which can be attributed to the so-called 'opacity effect'. This effect significantly determines the magnitude of radiative damping.

The Thermal Operating Environment of Corticolous and Pendulous Tree Lichens

The thallus temperatures of Hypogymnia physodes, Letharia vulpina and Usnea fulvoreagens during full solar radiation in contrasting canopy positions are compared with corre- sponding air temperature data. The thallus temperature of Hypogymnia growing in the boundary layer of the bark surface is always well above air temperature despite strong convectional cooling by wind in the canopy. Hypogymnia at ground level achieves even higher thallus temperatures in the absence of any marked degree of convective cooling. Usnea with its very fine branches and resultant high surface area to weight ratio radiates energy very efficiently and remains very close to air temperature. Letharia with its bulkier thallus and caespitose habit occupies an intermediate position with thallus temperatures rising to ca. 80C under full radiation conditions. The data are discussed in relation to the thermal limits and net photosynthetic temperature optima found in lichens and the importance of defining the thermal operating environment of lichens rather than the overall latitudinal climate is emphasized. Standard meteorological temperature data are al- ways measured under well ventilated, diffuse radia- tion conditions, at approximately one meter above the ground. Consequently the values obtained have little relevance to the actual temperature experi- enced by a lichen on the ground, although they may approximate the thallus temperatures of pendulous arboreal lichens. To appreciate the operating ther- mal environment of a lichen, it is instructive to first examine the energy processes at a soil surface. By day, temperatures are often highest at soil surface, as net radiant absorption leads to energy accumu- lation, while by night, the soil surface may experi- ence the lowest temperatures, as net radiant emis- sion leads to energy deficits. The amplitude of the diurnal temperature changes is thus greatest at the soil/air interface, often resulting in very steep ver- tical temperature profiles during high radiant emis- sion periods. Energy transfer from the soil surface is impeded by the presence of a thin layer of air, known as the laminar boundary layer, which ad- heres to the soil/air interface, and in which only laminar air flow is possible. This allows only radia- tive and non-convective molecular diffusion trans-