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.

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.

A reflexion on the environmental effect on the transmission of COVID-19

2021 ◽  
Author(s):  
Victor L Barradas ◽  
Monica Ballinas
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Low Temperatures ◽  
Minimum Distance ◽  
Vapor Pressure Deficit ◽  
Environmental Parameters ◽  
Air Humidity ◽  
Evaporative Demand ◽  
Small Water ◽  
The Hours

<p>This research is a general reflection of the possible transmission not only of COVID-19 but of any influenza disease depending on environmental parameters such as solar radiation, air humidity and air temperature (vapor pressure deficit), evoking the Penman-Monteith model regarding the evaporation of the water that constitutes the small water droplets (aerosols) that carry the virus. In this case the evapotranspiration demand of the atmosphere with which it can be deduced that the spread of the disease will be higher in those places with less evaporative demand, that is, high air humidity and / or low temperatures, and / or low radiation intensities, and vice versa. It can also be deduced that the hours of greatest potential contagion are the night hours, while those with the lowest risk are between 2:00 p.m. and 4:00 p.m. On the other hand, in those rooms with low temperatures the contagion would be more effective. So, considering that the drops produced by a sneeze, by speaking or breathing can go beyond two meters away, it is roughly explained that the use of face masks and keeping a safe minimum distance of two meters can limit transmission of viruses and / or infections. However, this practice is not entirely safe as the environment can play an important role. What is recommended to reduce the spread of these pathogens is to produce high evaporative demands: increasing solar radiation, and increasing air temperature and reducing air humidity, which is practice that can be effective in closed rooms.</p>

scholarly journals Changes in the timing and duration of the near-surface soil freeze/thaw status from 1956 to 2006 across China

2015 ◽  
Vol 9 (3) ◽  
pp. 1321-1331 ◽  
Author(s):  
K. Wang ◽  
T. Zhang ◽  
X. Zhong
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Surface Soil ◽  
Eastern China ◽  
Western China ◽  
Actual Number ◽  
Important Indicator ◽  
Near Surface ◽  
Freeze Thaw ◽  
Using Data

Abstract. The near-surface soil freeze/thaw status is an important indicator of climate change. Using data from 636 meteorological stations across China, we investigated the changes in the first date, the last date, the duration, and the number of days of the near-surface soil freeze over the period 1956–2006. The results reveal that the first date of the near-surface soil freeze was delayed by about 5 days, or at a rate of 0.10 ± 0.03 day yr−1, and the last date was advanced by about 7 days, or at a rate of 0.15 ± 0.02 day yr−1. The duration of the near-surface soil freeze decreased by about 12 days or at a rate of 0.25 ± 0.04 day yr−1, while the actual number of the near-surface soil freeze days decreased by about 10 days or at a rate of 0.20 ± 0.03 day yr−1. The rates of changes in the near-surface soil freeze/thaw status increased dramatically from the early 1990s through the end of the study period. Regionally, the changes in western China were greater than those in eastern China. Changes in the near-surface soil freeze/thaw status were primarily controlled by changes in air temperature, but urbanization may also play an important role.

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.

Twentieth-Century Surface Air Temperature over China and the Globe Simulated by Coupled Climate Models

2006 ◽  
Vol 19 (22) ◽  
pp. 5843-5858 ◽  
Author(s):  
Tianjun Zhou ◽  
Rucong Yu
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Air Temperature ◽  
Climate Models ◽  
Eastern China ◽  
Surface Air Temperature ◽  
Future Climate Change ◽  
Intergovernmental Panel ◽  
Coupled Climate Models ◽  
Anthropogenic Forcings

Abstract This paper examines variations of the surface air temperature (SAT) over China and the globe in the twentieth century simulated by 19 coupled climate models driven by historical natural and anthropogenic forcings. Most models perform well in simulating both the global and the Northern Hemispheric mean SAT evolutions of the twentieth century. The inclusion of natural forcings improves the simulation, in particular for the first half of the century. The reproducibility of the SAT averaged over China is lower than that of the global and hemispheric averages, but it is still acceptable. The contribution of natural forcings to the SAT over China in the first half of the century is not as robust as that to the global and hemispheric averages. No model could successfully produce the reconstructed warming over China in the 1920s. The prescribed natural and anthropogenic forcings in the coupled climate models mainly produce the warming trends and the decadal- to interdecadal-scale SAT variations with poor performances at shorter time scales. The prominent warming trend in the last half of the century over China and its acceleration in recent decades are weakly simulated. There are discrepancies between the simulated and observed regional features of the SAT trend over China. Few models could produce the summertime cooling over the middle part of eastern China (27°–36°N), while two models acceptably produce the meridional gradients of the wintertime warming trends, with north China experiencing larger warming. Limitations of the current state-of-the-art coupled climate models in simulating spatial patterns of the twentieth-century SAT over China cast a shadow upon their capability toward projecting credible geographical distributions of future climate change through Intergovernmental Panel on Climate Change (IPCC) scenario simulations.

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.

Sign in / Sign up

Export Citation Format

Share Document