scholarly journals Does evaporation paradox exist in China?

2009 ◽  
Vol 13 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Z. T. Cong ◽  
D. W. Yang ◽  
G. H. Ni
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Sunshine Duration ◽  
Warming Trend ◽  
Pan Evaporation ◽  
Weather Factors ◽  
The Past ◽  
Weather Stations ◽  
Rate Of Evaporation

Abstract. One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called "evaporation paradox". Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The conclusions include: (1) From 1956 to 2005, pan evaporation paradox existed in China as a whole while pan evaporation kept decreasing and air temperature became warmer and warmer, but it does not apply to Northeast and Southeast China; (2) From 1956 to 1985, pan evaporation paradox existed narrowly as a whole with unobvious climate warming trend, but it does not apply to Northeast China; (3) From 1986 to 2005, in the past 20 years, pan evaporation paradox did not exist for the whole period while pan evaporation kept increasing, although it existed in South China. Furthermore, the trend of other weather factors including sunshine duration, windspeed, humidity and vapor pressure deficit, and their relations with pan evaporation are discussed. As a result, it can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the decreasing in vapor pressure deficit due to strong warming after 1986. With the Budyko curve, it can be concluded that the actual evaporation decreased in the former 30 years and increased in the latter 20 year for the whole China.

scholarly journals Does evaporation paradox exist in China?

2008 ◽  
Vol 5 (4) ◽  
pp. 2111-2131 ◽  
Author(s):  
Z. T. Cong ◽  
D. W. Yang
Keyword(s):  
Global Warming ◽  
Wind Speed ◽  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Pan Evaporation ◽  
Weather Factors ◽  
The Past ◽  
The World ◽  
Weather Stations ◽  
Rate Of Evaporation

Abstract. One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called the evaporation paradox. Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The following conclusions were made: (1) From 1956 to 2005, pan evaporation paradox exists in China as a whole with decreasing in pan evaporation and the warming though it does not exist in Northeast and Southeast; (2) From 1956 to 1985, pan evaporation paradox exists narrowly as a whole with unobvious warming though it does not exist in Northeast (3) From 1986 to 2005, in the past 50 years, the precipitation and the pan evaporation exhibit contrary trend in most areas. Furthermore, pan evaporation paradox does not exist as a whole with increasing in pan evaporation though it exists in South. Furthermore, the trend of other weather factors including sunlight time, windspeed, humidity and vapor pressure deficit and their relation with pan evaporation are discussed. It can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the deceasing in vapor pressure deficit due to strong warming after 1986.

scholarly journals Projecting and Attributing Future Changes of Evaporative Demand over China in CMIP5 Climate Models

2017 ◽  
Vol 18 (4) ◽  
pp. 977-991 ◽  
Author(s):  
Wenbin Liu ◽  
Fubao Sun
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Climate Models ◽  
Eastern China ◽  
Irrigation Scheduling ◽  
Western China ◽  
Percentage Increase ◽  
Pan Evaporation ◽  
Evaporative Demand

Abstract Atmospheric evaporative demand plays a pivotal role in global water and energy budgets, and its change is very important for drought monitoring, irrigation scheduling, and water resource management under a changing environment. Here, future changes of pan evaporation Epan, a measurable indicator for atmospheric evaporative demand, are first projected and attributed over China through a physically based approach, namely, the PenPan model, forced with outputs from 12 state-of-the-art climate models from phase 5 of the Coupled Model Intercomparison Project. An equidistant quantile mapping method was also used to correct the biases in GCMs outputs to reduce uncertainty in Epan projection. The results indicated that Epan would increase during the periods 2021–50 and 2071–2100 relative to the baseline period 1971–2000 under the representative concentration pathway (RCP) 4.5 and 8.5 scenarios, which can mainly be attributed to the projected increase in air temperature and vapor pressure deficit over China. The percentage increase of Epan is relatively larger in eastern China than in western China, which is due to the spatially inconsistent increases in air temperature, net radiation, wind speed, and vapor pressure deficit over China. The widely reported “pan evaporation paradox” was not well reproduced for the period 1961–2000 in the climate models, before or after bias correction, suggesting discrepancy between observed and modeled trends. With that caveat, it was found that the pan evaporation has been projected to increase at a rate of 117–167 mm yr−1 K−1 (72–80 mm yr−1 K−1) over China using the multiple GCMs under the RCP 4.5 (RCP 8.5) scenario with increased greenhouse gases and the associated warming of the climate system.

Influence of canopy microclimate on incidence and severity of dogwood anthracnose

1992 ◽  
Vol 70 (5) ◽  
pp. 1093-1096 ◽  
Author(s):  
Dan O. Chellemi ◽  
Kerry O. Britton
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Vapor Pressure Deficit ◽  
Disease Incidence ◽  
Cornus Florida ◽  
Active Radiation ◽  
Dogwood Anthracnose ◽  
Low Levels ◽  
Understory Trees

Incidence and severity of dogwood anthracnose within the interior and exterior canopies of exposed dogwood (Cornus florida L.) trees and canopies of understory trees were recorded over a 53-day period during the summer of 1990. Concurrent measurements of vapor pressure deficit, air temperature, evaporative potential, and photosynthetically active radiation within the canopies were also recorded. Disease incidence was significantly lower in the exterior canopy of exposed trees than in other canopy locations. Disease severity was significantly different among all three canopy locations, with the lowest severity in exterior canopies of exposed trees and the greatest severity in canopies of understory trees. Of the climatic variables measured, evaporative potential provided the most consistent contrast among microclimates at the various canopy locations. Mean evaporative potentials averaged over 6- to 10-day intervals ranged from 0.00 g H2O h−1 in understory and exposed, interior canopies to 0.40 g H2O h−1 in exposed, exterior canopies. Disease incidence and severity were greater in canopies associated with low levels of evaporative potential. Key words: Cornus florida L., dogwood anthracnose, canopy microclimate, evaporative potential.

scholarly journals 096 QUANTIFYING THE EFFECT OF SUPPLEMENTAL LIGHTING ON PLANT TEMPERATURES IN GREENHOUSES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 442a-442
Author(s):  
James E. Faust ◽  
Royal D. Heins
Keyword(s):  
High Pressure ◽  
Vapor Pressure ◽  
Air Temperature ◽  
Catharanthus Roseus ◽  
Vapor Pressure Deficit ◽  
Shoot Tip ◽  
Total Radiation ◽  
Degree Day ◽  
Air Temperatures ◽  
Supplemental Lighting

The effects of supplemental lighting on vinca (Catharanthus roseus L.) plant temperature were quantified in greenhouses maintained at air temperatures of 15. 25, and 35C. High-pressure sodium (HPS) lamps delivering 100 μmol·m-2·s-1 PPF provided 73 W · m-2 of total radiation (400 to 50,000 nm) to lighted plants. Plant shoot-tip temperature was measured by using 40-gauge thermocouples. Relative to air temperature, plant shoot-tip temperature depended on the irradiance and vapor-pressure deficit (VPD). Irrespective of VPD, the additional irradiance absorbed by plants under the HPS lamps increased plant temperature 1 to 2°C. Under relatively low VPD conditions (1 kPa), plant temperature was greater than air temperature, while under high VPD conditions (4 to 5 kPa), temperature of both lighted and unlighted plants remained below air temperature throughout the day. Temperature of lighted plants however, remained 1 to 2°C above that of unlighted plants. Analysis of a degree-day model of vinca development showed hastened development associated with supplemental lighting could be explained by increased plant temperature rather than any specific photosynthetic effect.

scholarly journals Above- and Belowground Microclimate of Grow Tubes in an Organic Mulch-incorporated, Raised Bed System for Blueberry

HortScience ◽  
2013 ◽  
Vol 48 (11) ◽  
pp. 1363-1369
Author(s):  
Julie M. Tarara ◽  
Bernardo Chaves ◽  
Bernadine C. Strik
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Vaccinium Corymbosum ◽  
Temperature Data ◽  
Radiation Load ◽  
Organic Mulch ◽  
Woody Perennial ◽  
Soil Temperatures ◽  
Raised Bed

Grow tubes are well established in forestry and are gaining attention in establishing some woody perennial crops. To date, microclimate descriptions have addressed the aboveground environment, but a mulched raised bed system with organic mulch-incorporated soil requires both the above- and belowground microclimate to be quantified. We measured the microclimate of commercially used, non-ventilated translucent and non-ventilated opaque grow tubes in a model crop of blueberry (Vaccinium corymbosum L.) grown on sawdust-mulch-covered raised beds formed from sawdust-incorporated tilled soil. The differences in air temperature between tubes and ambient were consistent with those reported in the literature. Air temperature in translucent tubes was up to 19.7 °C higher than ambient. Differences in vapor pressure deficit were largely a function of differences in air temperature between tubes and ambient rather than actual vapor pressure. Stem temperatures were highest outside of the tubes as a result of radiation load. The surface temperature of ambient sawdust mulch (maximum 53 °C) was up to 14 °C above that in the translucent tube and 20 °C above that in the opaque tube. The largest gradients in the bed system were between the loose dry mulch and the soil–mulch interface. The presence of a grow tube did not influence soil temperature or its daily amplitude at 15 cm below the surface—the native tilled soil. Temperatures associated with the opaque tubes were between ambient and those in the translucent tubes. The temperature data indicate that both opaque and translucent unventilated grow tubes should influence shoot and crown growth but may have little influence on root growth in this shallow-rooted plant.

Trend of Surface Air Temperature in Eastern China and Associated Large-Scale Climate Variability over the Last 100 Years

2014 ◽  
Vol 27 (12) ◽  
pp. 4693-4703 ◽  
Author(s):  
Ping Zhao ◽  
Phil Jones ◽  
Lijuan Cao ◽  
Zhongwei Yan ◽  
Shuyao Zha ◽  
...  
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Eastern China ◽  
Surface Air Temperature ◽  
Tropical Indian Ocean ◽  
Population Data ◽  
Warming Trend ◽  
Climate Indices ◽  
The Past ◽  
Linear Trends

Abstract Using the reconstructed continuous and homogenized surface air temperature (SAT) series for 16 cities across eastern China (where the greatest industrial developments in China have taken place) back to the nineteenth century, the authors examine linear trends of SAT. The regional-mean SAT over eastern China shows a warming trend of 1.52°C (100 yr)−1 during 1909–2010. It mainly occurred in the past 4 decades and this agrees well with the variability in another SAT series developed from a much denser station network (over 400 sites) across this part of China since 1951. This study collects population data for 245 sites (from these 400+ locations) and split these into five equally sized groups based on population size. Comparison of these five groups across different durations from 30 to 60 yr in length indicates that differences in population only account for between 9% and 24% of the warming since 1951. To show that a larger urbanization impact is very unlikely, the study additionally determines how much can be explained by some large-scale climate indices. Anomalies of large-scale climate indices such as the tropical Indian Ocean SST and the Siberian atmospheric circulation systems account for at least 80% of the total warming trends.

scholarly journals Spatiotemporal Variations and Influencing Factors of Terrestrial Evapotranspiration and Its Components during Different Impoundment Periods in the Three Gorges Reservoir Area

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2111
Author(s):  
Yongyue Ji ◽  
Qingqing Tang ◽  
Lingyun Yan ◽  
Shengjun Wu ◽  
Liming Yan ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Three Gorges Reservoir ◽  
Vapor Pressure Deficit ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Climate Factors ◽  
Spatiotemporal Variations ◽  
Reservoir Area ◽  
The Three Gorges

Identifying the spatiotemporal variations and influencing climate factors of evapotranspiration (ET) and its components (vegetation transpiration (Ec), soil evaporation (Es), and canopy interception evaporation (Ei)) can greatly improve our understanding of water cycle, carbon cycle, and biogeochemical processes in a warming climate. As the world′s largest hydropower project, the construction of the Three Gorges Project (TGP) coupled with the significant land use/land cover change affected the regional water and energy exchange in the Three Gorges Reservoir Area (TGRA). This study aimed to reveal the spatiotemporal variations and influencing climate factors in ET and its components using PML-V2 products in TGRA during 2000–2020. Results showed that the mean annual ET, Ec, Es, and Ei in TGRA were 585.12, 328.49, 173.07, and 83.56 mm, respectively. The temporal variation of ET was dominated by Ec, with no significant change in the time trend. Es decreased (2.92 mm/y) and Ei increased (1.66 mm/y) significantly mainly in the cultivated land. ET, Ec, and Ei showed a similar seasonal variation pattern with a single peak, while Es presented a bimodal pattern. From the pre-impoundment to the first impoundment period, ET and Ec mainly increased in the head of TGRA, meanwhile, Es in urban area increased significantly by 27.8%. In the subsequent impoundment periods, ET and Ec changed slightly while Es sharply decreased. The Ei increased persistently during different impoundment period. The dominant climate factors affecting changes in Ec and Es were air temperature, vapor pressure deficit, and sunshine hours, while the variation of Ei was mainly affected by air temperature, vapor pressure deficit, and precipitation.

scholarly journals DESEMPENHO DE UM SISTEMA DE RESFRIAMENTO EVAPORATIVO DO AR EM CASA-DE-VEGETAÇÃO

Irriga ◽  
2010 ◽  
Vol 15 (2) ◽  
pp. 140-150
Author(s):  
Antonio José Steidle Neto ◽  
SÉRGIO ZOLNIER
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Cooling Efficiency ◽  
Growing Period ◽  
Air Cooling System

Este trabalho foi conduzido com o objetivo de analisar o desempenho de um sistema de resfriamento evaporativo do ar (tipo painel-exaustor) em casa-de-vegetação, ao longo do período diurno em dias com condições climáticas distintas. Foram realizadas medições de temperatura e umidade relativa do ar no interior e exterior de uma casa-de-vegetação durante o período de crescimento e desenvolvimento de tomateiros cultivados em substrato de areia. Verificou-se que as eficiências médias diárias de resfriamento evaporativo do ar variaram entre 74% e 81%. Os decréscimos máximos na temperatura do ar, imediatamente após a sua passagem pelo painel de celulose, foram de 8,2ºC e 11,4ºC. Observou-se ainda que, a eficiência de resfriamento do ar foi sensivelmente melhorada quando o déficit de pressão de vapor d'água do ar externo foi superior a 1,8 kPa.   UNITERMOS: déficit de pressão de vapor d'água do ar, temperatura do ar, eficiência de resfriamento evaporativo.     STEIDLE NETO, A. J.; ZOLNIER, S. EVAPORATIVE AIR COOLING SYSTEM PERFORMANCE IN A GREENHOUSE     2 ABSTRACT   This work aimed to analyze the performance of an evaporative air cooling system (pad-fan type) in greenhouse along daytime period in days with different climatic conditions. Air temperature and relative humidity measurements inside and outside of an greenhouse were made during the growing period of tomato plants cultivated in sand substrate. It was verified that the average daily evaporative cooling efficiency ranged from 74% to 81%. The maximum air temperature decrements, immediately after its passage through the cellulose pad, were 8.2°C and 11.4°C. It was also observed that the air cooling efficiency was sensitively improved when the vapor pressure deficit of the external air was higher than 1.8 kPa.   KEYWORDS: vapor pressure deficit, air temperature, evaporative cooling efficiency.  

scholarly journals VARIABILITY OF THE MAIN CLIMATIC INDICATORS IN THE TERRITORY OF THE VOLGA FEDERAL DISTRICT IN THE PERIOD 1966-2018

2021 ◽  
Vol 31 (1) ◽  
pp. 65-75
Author(s):  
Yu.P. Perevedentsev ◽  
E.M. Parubova ◽  
K.M. Shantalinsky ◽  
M.A. Myagkov ◽  
B.G. Sherstyukov
Keyword(s):  
Air Temperature ◽  
Annual Variation ◽  
Water Vapor Pressure ◽  
Atmospheric Precipitation ◽  
Statistical Processing ◽  
Federal District ◽  
Warming Trend ◽  
A Value ◽  
Weather Stations ◽  
Spatio Temporal

The spatio-temporal variability of air temperature and humidity, atmospheric precipitation in the Volga Federal District in 1966-2018 is considered. As a result of statistical processing of data from 20 weather stations, a clear warming trend in recent decades and a weak increase in annual precipitation are revealed, except for the south-east of the region. The annual variation of water vapor pressure and relative humidity is considered, statistics of the distribution of "dry" and "wet" days by stations in different months are carried out. Correlations between individual circulation modes (AO, NAO, SCAND, EAWR) and air temperature are revealed. It is shown that positive relationships are closer in winter with the AO and NAO indices than in summer. A sufficiently high negative correlation is established with the SCAND index in winter (r = -0,7), and with the EAWR index in summer (the correlation coefficient reaches a value of -0,6).

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