Prediction of daily mean vapor density from daily minimum air temperature

1992 ◽  
Vol 59 (3-4) ◽  
pp. 309-317 ◽  
Author(s):  
Keith L. Bristow
1988 ◽  
Vol 78 (2) ◽  
pp. 235-240 ◽  
Author(s):  
J. N. Matthiessen ◽  
M. J. Palmer

AbstractIn studies in Western Australia, temperatures in air and one- and two-litre pads of cattle dung set out weekly and ranging from one to 20 days old were measured hourly for 438 days over all seasons, producing 1437 day x dung-pad observations. Daily maximum temperatures (and hence thermal accumulation) in cattle dung pads could not be accurately predicted using meteorological data alone. An accurate predictor of daily maximum dung temperature, using multiple regression analysis, required measurement of the following factors: maximum air temperature, hours of sunshine, rainfall, a seasonal factor (the day number derived from a linear interpolation of day number from day 0 at the winter solstice to day 182 at the preceding and following summer solstices) and a dung-pad age-specific intercept term, giving an equation that explained a 91·4% of the variation in maximum dung temperature. Daily maximum temperature in two-litre dung pads was 0·6°C cooler than in one-litre pads. Daily minimum dung temperature equalled minimum air temperature, and daily minimum dung temperatures occurred at 05.00 h and maximum temperatures at 14.00 h for one-litre and 14.30 h for two-litre pads. Thus, thermal summation in a dung pad above any threshold temperature can be computed using a skewed sine curve fitted to daily minimum air temperature and the calculated maximum dung temperature.


2011 ◽  
Vol 151 (8) ◽  
pp. 1066-1073 ◽  
Author(s):  
Zachary A. Holden ◽  
John T. Abatzoglou ◽  
Charles H. Luce ◽  
L. Scott Baggett

Author(s):  
Sidinei Z. Radons ◽  
Arno B. Heldwein ◽  
Luís H. Loose ◽  
Mateus P. Bortoluzzi ◽  
Silvane I. Brand ◽  
...  

ABSTRACT There are several fields that require knowledge of air temperature variation throughout the day, such as disease prediction or calculation of chill-hours. However, automatic meteorological stations are not always located in the vicinity to accurately monitor this variable. In this sense, models that describe the daily temporal variation of air temperature can be used to meet this demand, and transform the climatic data series of conventional meteorological stations into an estimated hourly series. The aim of this study was to adjust and validate models for the hourly air temperature variation through data obtained at internationally agreed times (0, 12 and 18 h Universal Time Coordinated: UTC) and the daily minimum air temperature. The hourly database of the automatic station was used for model adjustment and validation. Functions were adjusted based on values measured at internationally agreed times and the daily minimum air temperature for certain daily variation patterns. The air temperature estimation was performed on an hourly basis using sinusoidal and linear models. The model that presented the lowest root mean square error (RMSE) was used for the estimation. The accuracy of the air temperature estimates varied according to the time, presenting RMSE from 0.7 to 1.6 °C, with maximum mean deviation of 0.4 °C. The results of this study showcase the necessity of knowledge of the daily air temperature variation, as well as a series of data from conventional meteorological stations, which can be estimated using hourly models.


2017 ◽  
Vol 56 (2) ◽  
pp. 519-533 ◽  
Author(s):  
Tomotsugu Yazaki ◽  
Hirokazu Fukushima ◽  
Tomoyoshi Hirota ◽  
Yukiyoshi Iwata ◽  
Atsushi Wajima ◽  
...  

AbstractWinter air temperatures strongly affect crop overwintering and cold resource usage. To clarify how winter air temperature distributions are formed in a mesoscale plain, field observations and simulations were conducted for the Tokachi region in Japan. Results elucidating the winter climate within the plain revealed that the winter mean air temperature at each site was correlated closely with the mean daily minimum air temperature. The daily minimum air temperature was not correlated with altitude, suggesting that local variation of the daily minimum temperature influences the temperature distribution. Observations at different distances from the upwind mountains revealed that nocturnal air temperatures were higher for stronger winds closer to the mountain foot. Low temperatures associated with wind speed suggest that radiative cooling strongly affects the temperature distribution. Wind and temperature conditions in the boundary layer influence the degree of drop in nocturnal air temperature and its distribution. The wind speed and direction, respectively, affect the extent and direction of the high-temperature zone from the northwest mountain foot. Simulations with a spatial resolution of 2 km reproduced the observed temperatures, but the error exceeded 5°C at sites having complex terrain under moderate or strong wind conditions. A higher-resolution model of 0.5 km showed that simulated temperatures approach the observed temperatures in association with a local wind system of down-valley drainage flow. In conclusion, the synoptic background, wind strength and direction over the plain, and microscale valleys affect boundary layer mixing and, thereby, determine the winter air temperature distribution.


2021 ◽  
Vol 13 (6) ◽  
pp. 1177
Author(s):  
Peijuan Wang ◽  
Yuping Ma ◽  
Junxian Tang ◽  
Dingrong Wu ◽  
Hui Chen ◽  
...  

Tea (Camellia sinensis) is one of the most dominant economic plants in China and plays an important role in agricultural economic benefits. Spring tea is the most popular drink due to Chinese drinking habits. Although the global temperature is generally warming, spring frost damage (SFD) to tea plants still occurs from time to time, and severely restricts the production and quality of spring tea. Therefore, monitoring and evaluating the impact of SFD to tea plants in a timely and precise manner is a significant and urgent task for scientists and tea producers in China. The region designated as the Middle and Lower Reaches of the Yangtze River (MLRYR) in China is a major tea plantation area producing small tea leaves and low shrubs. This region was selected to study SFD to tea plants using meteorological observations and remotely sensed products. Comparative analysis between minimum air temperature (Tmin) and two MODIS nighttime land surface temperature (LST) products at six pixel-window scales was used to determine the best suitable product and spatial scale. Results showed that the LST nighttime product derived from MYD11A1 data at the 3 × 3 pixel window resolution was the best proxy for daily minimum air temperature. A Tmin estimation model was established using this dataset and digital elevation model (DEM) data, employing the standard lapse rate of air temperature with elevation. Model validation with 145,210 ground-based Tmin observations showed that the accuracy of estimated Tmin was acceptable with a relatively high coefficient of determination (R2 = 0.841), low root mean square error (RMSE = 2.15 °C) and mean absolute error (MAE = 1.66 °C), and reasonable normalized RMSE (NRMSE = 25.4%) and Nash–Sutcliffe model efficiency (EF = 0.12), with significantly improved consistency of LST and Tmin estimation. Based on the Tmin estimation model, three major cooling episodes recorded in the "Yearbook of Meteorological Disasters in China" in spring 2006 were accurately identified, and several highlighted regions in the first two cooling episodes were also precisely captured. This study confirmed that estimating Tmin based on MYD11A1 nighttime products and DEM is a useful method for monitoring and evaluating SFD to tea plants in the MLRYR. Furthermore, this method precisely identified the spatial characteristics and distribution of SFD and will therefore be helpful for taking effective preventative measures to mitigate the economic losses resulting from frost damage.


Parasitology ◽  
1941 ◽  
Vol 33 (3) ◽  
pp. 331-342 ◽  
Author(s):  
H. J. Craufurd-Benson

1. The geographical distribution of cattle lice in Britain is recorded in detail. Bovicola bovis is the commonest and most widely distributed species in Britain.2. The incubation period for the eggs was found to be: Haematopinus eurysternus, 9–19 days (av. 12); Bovicola bovis, 7–10 days (av. 8); Linognathus vitula, 10–13 days; Solenopotes capillatus, 10–13 days. With eggs of H. eurysternus it was found that the higher the minimum air temperature the shorter was the incubation period.3. In H. eurysternus the average length of the instars was: 1st, 4 days; 2nd, 4 days; 3rd, 4 days; pre-oviposition period, 3–4 days. The average time for the complete life cycle, egg to egg, was 28 days.4. The maximum longevity of H. eurysternus on the host was: males, 10 days; females, 16 days. No males or females of H. eurysternus survived a starvation period of 72 hr. at 20° C. and R.H. 70 or 0–10° C. and R.H. 70–85; but some nymphs survived this period at 20° C. and R.H. 70, but none survived 96 hr. starvation.5. The maximum number of eggs recorded for one female was 24; and eggs were laid at the rate of 1–4 a day.6. The threshold of development of the eggs of H. eurysternus appears to be about 27·5° C.


1988 ◽  
Vol 74 (3) ◽  
pp. 181-186
Author(s):  
S. P. L. Travis

AbstractThe surface temperature of eight Royal Marine recruits was monitored in the field during Autumn training on Dartmoor (minimum air temperature 4.5°C). The lowest skin temperature recorded was 6.1°C. One subject experienced a toe temperature below 10° for 5.5 hours and below 15°C for 12.6 hours during a 24 hour recording period. Ambient temperature and inactivity during exposure to cold were the main factors associated with low toe temperatures but individual responses varied widely.


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