scholarly journals Spatiotemporal Patterns and Trends of Precipitation and Their Correlations with Related Meteorological Factors by Two Sets of Reanalysis Data in China

2018 ◽  
Author(s):  
Jinhui Jeanne Huang ◽  
Nan Zhang ◽  
Gyewoon Choi ◽  
Edward Arthur McBean ◽  
Qian Zhang
Keyword(s):  
Tibetan Plateau ◽  
Latent Heat ◽  
Air Temperature ◽  
Surface Pressure ◽  
Strong Correlation ◽  
Meteorological Factors ◽  
Wave Radiation ◽  
Monsoon Region ◽  
Long Wave ◽  
Long Wave Radiation

Abstract. This paper investigates the spatial-temporal characteristics of the changes in precipitation for China and the influence of other meteorological factors on precipitation. Two reanalysis datasets at monthly scale, namely, the GLDAS2 phase 2 forcing data 0.5 × 0.5 (1948 ~ 2008) and National Centers for Environmental Prediction (NCEP) data were employed. The Mann-Kendall trend test identified the annual and seasonal changes in four meteorological factors for precipitation, air temperature, long wave radiation and surface pressure. Confidence levels of 95 % were taken as thresholds to classify the significance of positive and negative trends. The trend analysis was conducted in three storm zones (I-Eastern Monsoon Region, II-Northern Inland Region and III-Qinghai-Tibetan Plateau Region) specified by Wang (2002). The findings indicate: 1) Air temperature, specific humidity and downward long wave radiation, have strong correlation with precipitation, especially for the eastern monsoon region of China; while surface pressure has very weak correlation with precipitation. 2) Latent heat shows very strong correlation with precipitation throughout China except for a small, extremely arid area in north China where large portions of the area are deserts. 3) The correlation between the volumetric soil moisture with precipitation and latent heat are controlled by precipitation with the characteristics of high annual precipitation and high correlations. 4) For precipitation, an increasing tendency in precipitation for the southeastern monsoon region and a decreasing tendency for the northeastern monsoon region (the drier region) were observed. 5) Strong increasing tendencies for air temperature and downward long wave radiation, were observed in the northeastern monsoon region and the western area of Qinghai-Tibetan Plateau. 6) Due to changes in precipitation and air temperature and downward long wave radiation, the scarcity of water resources in northeastern monsoon region and flooding problems in southeastern monsoon region may become more severe. 7) The study shows that agricultural development in China may require a shift between northern and western areas to adapt to the shift in precipitation patterns.

Micro-Meteorological Conditions for Snow Melt

1987 ◽  
Vol 33 (113) ◽  
pp. 24-26 ◽  
Author(s):  
M. Kuhn
Keyword(s):  
Boundary Layer ◽  
Transfer Coefficient ◽  
Air Temperature ◽  
Short Wave ◽  
Wave Radiation ◽  
Free Atmosphere ◽  
Alpine Glacier ◽  
Long Wave ◽  
Air Temperatures ◽  
Long Wave Radiation

AbstractThe energy budget of a snow or ice surface is determined by atmospheric variables like solar and atmospheric long-wave radiation, air temperature, and humidity; the transfer of energy from the free atmosphere to the surface depends on the stability of the atmospheric boundary layer, where vertical profiles of wind speed and temperature determine stability, and on surface conditions like surface temperature (and thus surface humidity), roughness, and albedo.This paper investigates the conditions exactly at the onset or the end of melting using air temperature, humidity, and as the radiation term the sum of global and reflected short-wave plus downward long-wave radiation. For the turbulent exchange in the boundary layer, examples are computed with a transfer coefficient of 18.5 W m−2K−1which corresponds to the average over the ablation period on an Alpine glacier. Ways to estimate the transfer coefficient for various degrees of stability are indicated in the Appendix.It appears from such calculations that snow may melt at air temperatures as low as –10°C and may stay frozen at +10°C.

The Meteorological Impact to the Air Temperature on a Sub-Tropical City

2014 ◽  
Vol 905 ◽  
pp. 374-378
Author(s):  
Chih Hong Huang ◽  
John Cua Aganda
Keyword(s):  
Air Temperature ◽  
Minimum Temperature ◽  
Wave Radiation ◽  
Urban Air ◽  
Temperature Pattern ◽  
Long Wave ◽  
The Difference ◽  
Meteorological Impact ◽  
The City ◽  
Long Wave Radiation

This study will center on the meteorological impact of clouds and its influence to the urban air temperature. Quantitative assessment over the behavior and temperature pattern was done using a five-year data of meteorological parameters obtain from the local weather and climate bureau. Urban heat island (UHI) is defined as the increased air temperature of the city over its surrounding sub-urban and rural areas and in this case of a five-year summer period of Taipei, Taiwan were heat temperatures are higher and can go beyond 39°C, acting dominant meteorological cloud cover factor is observe for its effect in temperature pattern. Analysis of local heat characteristics suggests the possibility of the believed theory Urban-scaled greenhouse effect that maybe affecting the patterns of the urban air temperature. An urban-scaled greenhouse effect is a theory that implies; when dense cloud covers the city, most of the supposed released long wave radiation or heat energy is trapped and reflected back by the dense clouds, creating a body of conserved heat that is prolonged in the area. The duration of conserved heat (DCH) is measured by the difference of the diurnal maximum and minimum temperature. To assess the value of the theory the daily cloud amount (CA) and its relationship with the DCH was tested with regression analysis. Calm days with the complete cycle of maximum and minimum temperature accordingly were selected and tested. The five-year average (2008 – 2012) resulted in a regression value of R2 = 0.072. Although the years 2011 & 2012 showed a higher regression value of R2 = 0.265 and R2 = 0.104 respectively, certainly enough the data of years 2011 and 2012 revealed a higher ratio of days with less combination of high wind speed and rainfall which created less fluctuations. Trend pattern for the five summers showed similarities. Some days showed fluctuation but no negative trend of correlation was detected. The heat intensity (HI) is another type of temperature pattern that was observed against CA and DCH, it is characterized by the difference of maximum and minimum diurnal temperature. Suggestive with our analysis, all five-year summertime data of HI showed negative correlation with the CA and DCH, attesting a faster release of long wave radiation when clouds are less.

scholarly journals Micro-Meteorological Conditions for Snow Melt

1987 ◽  
Vol 33 (113) ◽  
pp. 24-26 ◽  
Author(s):  
M. Kuhn
Keyword(s):  
Boundary Layer ◽  
Transfer Coefficient ◽  
Air Temperature ◽  
Short Wave ◽  
Wave Radiation ◽  
Free Atmosphere ◽  
Alpine Glacier ◽  
Long Wave ◽  
Air Temperatures ◽  
Long Wave Radiation

AbstractThe energy budget of a snow or ice surface is determined by atmospheric variables like solar and atmospheric long-wave radiation, air temperature, and humidity; the transfer of energy from the free atmosphere to the surface depends on the stability of the atmospheric boundary layer, where vertical profiles of wind speed and temperature determine stability, and on surface conditions like surface temperature (and thus surface humidity), roughness, and albedo.This paper investigates the conditions exactly at the onset or the end of melting using air temperature, humidity, and as the radiation term the sum of global and reflected short-wave plus downward long-wave radiation. For the turbulent exchange in the boundary layer, examples are computed with a transfer coefficient of 18.5 W m−2 K−1 which corresponds to the average over the ablation period on an Alpine glacier. Ways to estimate the transfer coefficient for various degrees of stability are indicated in the Appendix.It appears from such calculations that snow may melt at air temperatures as low as –10°C and may stay frozen at +10°C.

scholarly journals Surface energy exchanges above two grassland ecosystems on the Qinghai-Tibetan Plateau

2009 ◽  
Vol 6 (5) ◽  
pp. 9161-9192 ◽  
Author(s):  
S. Liu ◽  
S.-G. Li ◽  
G.-R. Yu ◽  
X.-M. Sun ◽  
L.-M. Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Surface Energy ◽  
Soil Water ◽  
Bowen Ratio ◽  
Energy Partitioning ◽  
Wave Radiation ◽  
Annual Variations ◽  
Long Wave ◽  
Energy Exchanges ◽  
Long Wave Radiation

Abstract. This paper explores the seasonal and inter-annual variations in surface energy exchanges at an alpine shrub-meadow ecosystem (AM) and an alpine meadow-steppe (AS) on the Qinghai-Tibetan Plateau using the 4–5-year continuous flux measurements by the eddy covariance technique. Although ground solar radiation (Kd) was lower at AM than at AS, net radiation (Rn) was higher at AM than at AS due to the lower surface reflectivity for short-wave radiation (albedo) and the lower ratio of upward long-wave radiation to downward long-wave radiation (Lu/Ld) at AM. The ratio of Rn/Kd was lower (about 0.4) at AS than at AM (about 0.6). In the annual scale, annual precipitation was the most important factor controlling energy partitioning at AS, while temperature, especially during the spring, controlled the inter-annual variations in energy partitioning at AM characterized by low temperature. Vegetation growth played an important role in controlling energy partitioning at seasonal scale at both sites. However, soil water content was also one of major factors affecting Bowen ratio (β) due to the lower soil water-holding capacity at AS as compared with AM. Under non-drought conditions, the influence of vapor pressure deficit (VPD) on energy partitioning at half-hourly scale was stronger at AM than at AS due to higher vegetation cover thereof.

Performance Characteristics of Sanborn Rod Thermistors

1952 ◽  
Vol 33 (2) ◽  
pp. 67-72 ◽  
Author(s):  
Raymond C. Staley
Keyword(s):  
Air Temperature ◽  
Temperature Compensation ◽  
Performance Characteristics ◽  
Wave Radiation ◽  
Long Wave ◽  
Accuracy Of Measurement ◽  
Long Wave Radiation

One type of Sanborn rod thermistor is studied with respect to the accuracy of measurement of air temperature. Compensation techniques are reviewed and inaccuracies, uncertainties, and lag coefficients are evaluated. Shielding of thermistors from solar and long-wave radiation is examined. With yearly calibration and proper shielding, temperatures may be measured with an accuracy of at least 0.4C°.

Influence of shelter on night temperatures, frost damage, and bud break of white spruce seedlings

1996 ◽  
Vol 26 (9) ◽  
pp. 1531-1538 ◽  
Author(s):  
Arthur Groot ◽  
Derek W. Carlson
Keyword(s):  
Air Temperature ◽  
White Spruce ◽  
Frost Damage ◽  
Wave Radiation ◽  
View Factor ◽  
Bud Break ◽  
Long Wave ◽  
Forest Openings ◽  
Long Wave Radiation ◽  
Minimum Air Temperature

Measurements of frost damage and bud-break phenology were made during the spring of 1993 and 1994 on planted white spruce (Piceaglauca (Moench) Voss) seedlings and on trembling aspen (Populustremuloides Michx.) suckers in combination with measurements of minimum air temperature and long-wave radiation in forest openings of different sizes and configurations (1.5-ha clearcut, 9 and 18 m wide strips, 9 and 18 m diameter circular openings and intact forest) near Chapleau, Ontario. The average minimum air temperature during early summer (May–June) decreased linearly as the sky view factor of the forest openings increased. The average difference in minimum air temperature between the forest and clearcut opening was nearly 3 °C for the period, and during clear night sky conditions, this temperature difference approached 6 °C. The difference in minimum temperature between the forest and clearcut during cloudy night sky conditions was slightly greater than 1 °C. Differences in minimum air temperature between the forest and each of the openings increased with decreasing incoming long-wave radiation. The largest differences occurred between the forest and the clearcut with low incoming long-wave radiation (cloudless nights). Minimum air temperatures in the 9-m strip and 9-m circle differed little from minimums in the forest under all long-wave radiation regimes. Moderation of air temperature on clear nights would be best achieved with sky view factors of less than 0.3, implying a maximum strip width of 0.6 tree heights and a maximum patch diameter of 2.2 tree heights. Damage to white spruce seedlings after a frost in the spring of 1993 increased with increasing sky view factor. Nearly 75% of the seedlings in the clear-cut had medium or heavy frost damage, while only 2% of the seedlings in the 9-m circle and forest were frost damaged. Opening size and configuration had little influence on the timing of bud break in either the white spruce seedlings or the trembling aspen suckers.

scholarly journals The Influence of Cloudiness on The Net Radiation Balance of A Snow Surface with High Albedo

1974 ◽  
Vol 13 (67) ◽  
pp. 73-84 ◽  
Author(s):  
W. Ambach
Keyword(s):  
Greenland Ice Sheet ◽  
Short Wave ◽  
Mean Value ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Net Radiation ◽  
Long Wave ◽  
Energy Excess ◽  
Overcast Sky ◽  
Long Wave Radiation

The short-wave and long-wave radiant fluxes measured in the accumulation area of the Greenland ice sheet during a mid-summer period are discussed with respect to their dependence on cloudiness. At a cloudiness of 10/10, a mean value of 270 J/cm2 d is obtained for the daily totals of net radiation balance, whereas a mean value of only 75 J/cm2 d is observed at 0/10. The energy excess of the net radiation balance with overcast sky is due to the significant influence of the incoming long-wave radiation and the high albedo of the surface (average of 84%). High values of net radiation balance are therefore correlated with high values of long-wave radiation balance and low values of short-wave radiation balance.

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