Influence of Below-Cloud Evaporation on Deuterium Excess in Precipitation of Arid Central Asia and Its Meteorological Controls

Abstract The deuterium excess is a second-order parameter linking water-stable oxygen and hydrogen isotopes and has been widely used in hydrological studies. The deuterium excess in precipitation is greatly influenced by below-cloud evaporation through unsaturated air, especially in an arid climate. Based on an observation network of isotopes in precipitation of arid central Asia, the difference in deuterium excess from cloud base to ground was calculated for each sampling site. The difference on the southern slope of the Tian Shan is generally larger than that on the northern slope, and the difference during the summer months is greater than that during the winter months. Generally, an increase of 1% in evaporation of raindrops causes deuterium excess to decrease by approximately 1‰. Under conditions of low air temperature, high relative humidity, heavy precipitation, and large raindrop diameter, a good linear correlation is exhibited between evaporation proportion and difference in deuterium excess, and a linear regression slope of <1‰ %−1 can be seen; in contrast, under conditions of high air temperature, low relative humidity, light precipitation, and small raindrop diameter, the linear relationship is relatively weak, and the slope is much larger than 1‰ %−1. A sensitivity analysis under different climate scenarios indicates that, if air temperature has increased by 5°C, deuterium excess difference decreases by 0.3‰–4.0‰ for each site; if relative humidity increases by 10%, deuterium excess difference increases by 1.1‰–10.3‰.

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Modeling Insights into Precipitation Deuterium Excess as an Indicator of Raindrop Evaporation in Lanzhou, China

Water ◽

10.3390/w13020193 ◽

2021 ◽

Vol 13 (2) ◽

pp. 193

Author(s):

Fenli Chen ◽

Mingjun Zhang ◽

Athanassios A. Argiriou ◽

Shengjie Wang ◽

Qian Ma ◽

...

Keyword(s):

Arid Region ◽

Quantitative Methods ◽

Isotope Composition ◽

Sampling Site ◽

Western China ◽

Cloud Base ◽

Deuterium Excess ◽

Semi Arid Region ◽

Semi Arid

The deuterium excess in precipitation is an effective indicator to assess the existence of sub-cloud evaporation of raindrops. Based on the synchronous measurements of stable isotopes of hydrogen and oxygen (δ2H and δ18O) in precipitation for several sites in Lanzhou, western China, spanning for approximately four years, the variations of deuterium excess between the ground and the cloud base are evaluated by using a one-box Stewart model. The deuterium excess difference below the cloud base during summer (−17.82‰ in Anning, −11.76‰ in Yuzhong, −21.18‰ in Gaolan and −12.41‰ in Yongdeng) is greater than that in other seasons, and difference in winter is weak due to the low temperature. The variations of deuterium excess in precipitation due to below-cloud evaporation are examined for each sampling site and year. The results are useful to understand the modification of raindrop isotope composition below the cloud base at a city scale, and the quantitative methods provide a case study for a semi-arid region at the monsoon margin.

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Seasonal variation of radon and CO2 in the Važecká Cave, Slovakia

Nukleonika ◽

10.2478/nuka-2020-0025 ◽

2020 ◽

Vol 65 (2) ◽

pp. 153-157

Author(s):

Iveta Smetanová ◽

Karol Holý ◽

Ľubica Luhová ◽

Kristian Csicsay ◽

Dagmar Haviarová ◽

...

Keyword(s):

Seasonal Variation ◽

Relative Humidity ◽

Air Temperature ◽

Radon Concentration ◽

Continuous Monitoring ◽

Annual Variation ◽

Activity Concentration ◽

Atmospheric Temperature ◽

Annual Maximum ◽

The Difference

AbstractThe continuous monitoring of 222Rn activity concentration, CO2 concentration, and microclimatologic parameters (internal air temperature and relative humidity) in the Važecká Cave (Northern Slovakia) is being carried out at three monitoring stations, namely, Gallery, Lake Hall, and Entrance Hall. Radon activity concentration and CO2 concentration exhibited a clear annual variation. The daily average of radon concentration ranged 1300–27 700 Bq/m3 at the Lake Hall station and 3600–42 200 Bq/m3 at the Gallery station. Radon reached its maximum in the summer months, from June to September. The annual maximum of CO2 concentration is registered approximately one month later than radon maximum. The annual variation of radon and CO2 is controlled by the seasonal change of ventilation regime associated with the seasonal variation of the difference between the temperature measured inside the cave and the atmospheric temperature.

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The relation of drainage to rainfall and other meteorological factors

The Journal of Agricultural Science ◽

10.1017/s0021859600048450 ◽

1941 ◽

Vol 31 (1) ◽

pp. 110-115 ◽

Cited By ~ 8

Author(s):

P. N. Sahni

Keyword(s):

Relative Humidity ◽

Wind Velocity ◽

Air Temperature ◽

Meteorological Factors ◽

Curvilinear Relationship ◽

The Mean ◽

The Difference ◽

June July

Natural drainage periods, i.e. periods between consecutive cessations of flow of the Rothamsted 20 in. drain gauge, were selected for the months of June, July and August. All periods of from 2 to 13 days were taken.A curvilinear relationship between the difference of rainfall and drainage (deficit) and rainfall was established.Residuals from this curve showed no appreciable correlation with the mean air temperature, but there was some slight evidence that the deficit was increased by a decrease in relative humidity or an increase in wind velocity.The residuals showed little correlation with drainage during the previous 3 weeks.

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Quantitative Analysis of the Sub-Cloud Evaporation of Atmospheric Precipitation and Its Controlling Factors Calculated By D-Excess in an Inland River Basin of China

Water ◽

10.3390/w12102798 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2798

Author(s):

Xinggang Ma ◽

Wenxiong Jia ◽

Guofeng Zhu ◽

Shijin Wang

Keyword(s):

Relative Humidity ◽

River Basin ◽

Sampling Site ◽

Atmospheric Precipitation ◽

Controlling Factors ◽

Qilian Mountains ◽

Cloud Base ◽

Near Surface ◽

Precipitation Decrease ◽

Excess Value

Atmospheric precipitation is an important part of the water circle in an inland basin. Based on the analytical results of 149 precipitation samples and corresponding surface meteorological data collected at four sampling sites (Lenglong, Ningchang, Huajian and Xiying) at different elevations in the Xiying river basin on the north slope of Qilian Mountains from May to September 2017, the sub-cloud evaporation in precipitation and its controlling factors are analyzed by the Stewart model. The results show that sub-cloud evaporation led to d-excess value in precipitation decrease and d-excess variation from cloud-base to near surface (Δd) increase with decreasing altitude. The remaining evaporation fraction of raindrop (f) decreases with decreasing altitude. The difference of underlying surface led to a difference change of f and Δd in the Xiying sampling site. For every 1% increase in raindrop evaporation, d-excess value in precipitation decreased by about 0.99‰. In an environment of high relative humidity and low temperature, the slope of the linear relationship between f and Δd is less than 0.99. In contrast, in the environment of low relative humidity and high temperature, the slope is higher than 0.99. In this study, set constant raindrop diameter may affect the calculation accuracy. The Stewart model could have different parameter requirements in different study areas. This research is helpful to understand water cycle and land–atmosphere interactions in Qilian Mountains.

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Reducing misclassified precipitation phase in conceptual models using cloud base heights and relative humidity to adjust air temperature thresholds

Hydrology Research ◽

10.2166/nh.2021.072 ◽

2021 ◽

Author(s):

Lic James M. Feiccabrino

Keyword(s):

Relative Humidity ◽

Air Temperature ◽

Conceptual Models ◽

Phase Changes ◽

Cloud Base ◽

Temperature Threshold ◽

Air Temperatures ◽

Low Cloud ◽

Precipitation Phase ◽

Cloud Base Height

Abstract In cold region, conceptual models assigned precipitation phase, liquid (rain) or solid (snow), cause vastly different atmospheric, hydrological, and ecological responses, along with significant differences in evaporation, runoff, and infiltration fates for measured precipitation mass. A set air temperature threshold (ATT) applied to the over 30% annual precipitation events occurring with surface air temperatures between −3 and 5 °C resulted in 11.0 and 9.8% misclassified precipitation in Norway and Sweden, respectively. Surface air temperatures do not account for atmospheric properties causing precipitation phase changes as snow falls toward the ground. However, cloud base height and relative humidity (RH) measured from the surface can adjust ATT for expected hydrometeor-atmosphere interactions. Applying calibrated cloud base height ATTs or a linear RH function for Norway (Sweden) reduced to 4.3% (2.8%) and 14.6% (8.9%) misclassified precipitation, respectively. Cloud base height ATTs had lower miss-rates with low cloud bases, 100 m in Norway and 300 m in Sweden. Combining the RH method with cloud base ATT in low cloud conditions resulted in 16.1 and 10.8% reduction in misclassified precipitation in Norway and Sweden, respectively. Therefore, the conceptual model output should improve through the addition of available surface data without coupling to an atmospheric model.

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Global Heat Wave Hazard Considering Humidity Effects during the 21st Century

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16091513 ◽

2019 ◽

Vol 16 (9) ◽

pp. 1513 ◽

Cited By ~ 6

Author(s):

Xi Chen ◽

Ning Li ◽

Jiawei Liu ◽

Zhengtao Zhang ◽

Yuan Liu

Keyword(s):

Relative Humidity ◽

Heat Wave ◽

Air Temperature ◽

Greenhouse Gas Emission ◽

Heat Waves ◽

Surface Air Temperature ◽

Heat Index ◽

Humidity Effects ◽

The Difference ◽

Heat Hazard

Humidity is a significant factor contributing to heat stress, but without enough consideration in studies of quantifying heat hazard or heat risk assessment. Here, the simplified wet-bulb globe temperature (WBGT) considering joint effects of temperature and humidity was utilized as a heat index and the number of annual total heat wave days (HWDs) was employed to quantify heat hazard. In order to evaluate the humidity effects on heat waves, we quantified the difference in the number of HWDs over global land based on air temperature and WBGT. Spatial and temporal changes in surface air temperature, relative humidity, WBGT, and the difference in HWDs were analyzed using multi-model simulations for the reference period (1986–2005) and different greenhouse gas emission scenarios. Our analysis suggests that annual mean WBGT has been increasing since 1986, which is consistent with the rising trend in surface air temperature despite a slight decrease in relative humidity. Additionally, changes in annual mean WBGT are smaller and more spatially uniform than those in annual mean air temperature as a cancelation effect between temperature and water vapor. Results show that there is an underestimation of around 40–140 days in the number of HWDs per year in most regions within 15° latitude of the equator (the humid and warm tropics) during 2076–2095 without considering humidity effects. However, the estimation of HWDs has limited distinction between using WBGT and temperature alone in arid or cold regions.

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Sanitary and hygienic condition of the microclimate parameters of the premises of light-frame and reconstructed cowsheds in the spring with loose housing of the dairy herd

145 - Tehnologìâ virobnictva ì pererobki produktìv tvarinnictva ◽

10.33245/2310-9289-2021-164-1-65-73 ◽

2021 ◽

pp. 65-73

Author(s):

V. Gryshko ◽

Y. Balatskyi

Keyword(s):

Relative Humidity ◽

Air Temperature ◽

Average Rate ◽

Dairy Herd ◽

Natural Light ◽

Metal Structures ◽

The Third ◽

Air Movement ◽

Number Of Factors ◽

The Difference

A comparative evaluation of the main parameters of the air microclimate for the maintenance of a dairy herd of cows in the reconstructed and light frame cowsheds in the spring was carried out. It was found that the average daily air temperature in the cowshed of light frame type of metal structures in the spring ranged from 5.48 to 16.42 ° C. Relative humidity in the spring ranged from 67.32 (third decade, at 12 o'clock) to 72.54% (at 6 o'clock in the morning in the first decade of research). Air velocities during the study period ranged on average from 0.29 (first decade at 15th hour) to 0.52 m/s (at 18 o’clock in the second decade of the study). On average, during the first, second and third decades, the level of natural light in the light frame cowshed was: 1981.05; 1942.72 and 2414.89 lux. In the reconstructed cowshed for the period of researches the lowest air temperature (° C) was fixed at the beginning of research as of 6 o'clock in the morning - 6,28 ° C, and the highest for the third decade - 17,86 ° C, at 15 o'clock. The relative humidity ranged from 67.74 to 74.12% (at 6 a.m. in the first decade of the study). The air velocity ranged from 0.39 to 0.42 m/s. The average rate of acceleration of air movement for the first, second and third decades was, respectively: 0.35; 0.41 and 0.34 m/s. The difference between the highest average (second decade) and the lowest (third decade) was 20.58%. In the reconstructed cowshed, the lowest indicator of natural light was recorded at the beginning of the research in the first decade at 6 o'clock in the morning - 1245.38 lux, and the highest in the third decade - 2481.51 lux, at 15 o'clock. On average for the first, second and third decades, the level of natural light in the reconstructed barn, respectively, was: 2000.06; 2075.15 and 2236.74 lux. It is established that the formation of the parameters of the air microclimate both in the room as a whole and in some of its individual parts is influenced by a number of factors, both external and internal. As a result, it was concluded that the parameters of the air microclimate in both cowsheds, although they had some differences, but in general met the established hygienic standards. Key words: microclimate parameters, air temperature, relative humidity, air movement, natural light, light frame cowshed, reconstructed cowshed, spring period, loose boxes of the dairy herd.

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Simulation analysis and optimization research on cooling and dehumidifying effects for evaporator

Thermal Science ◽

10.2298/tsci191125167l ◽

2020 ◽

pp. 167-167

Author(s):

Shuailing Liu ◽

Guoyuan Ma ◽

Shuxue Xu ◽

Fuping Li ◽

Chenzhe Hang

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Moisture Content ◽

Linear Relationship ◽

Air Temperature ◽

Simulation Analysis ◽

Evaporation Temperature ◽

Temperature And Humidity ◽

The Difference

The improvement performance of refrigerating dehumidification system was theoretically discusses based on a dehumidification model. The influence of evaporator inlet wind speed, dry bulb temperature and relative humidity on dehumidification were analysed by the model. The results show that, when inlet air temperature and humidity were kept constant, the dehumidification capacity increased first and then decreased with increase of the wind speed; When the moisture content and the wind speed of the inlet air were kept constant, the dehumidification capacity gradually decreased with increase of the inlet air dry bulb temperature; The inlet air dry bulb temperature was between 21-36 ?C and the relative humidity was between 40% and 85%, the difference between the inlet air wet bulb temperature and the evaporation temperature at the optimum COP was about 10 ?C; There was a nearly linear relationship between the corresponding evaporation temperature at the optimal COP and the evaporation temperature with the maximum dehumidification capacity, compared with the test value, the error was less than 10%.

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Pengaruh Kondisi Ketinggian Tempat Terhadap Produksi dan Mutu Tembakau Temanggung

Buletin Tanaman Tembakau Serat & Minyak Industri ◽

10.21082/bultas.v2n2.2010.45-59 ◽

2016 ◽

Vol 2 (2) ◽

pp. 45

Author(s):

Elda Nurnasari ◽

. Djumali

Keyword(s):

Relative Humidity ◽

Air Temperature ◽

Treatment Result ◽

Nicotine Content ◽

Central Java ◽

Yield And Quality ◽

The Difference ◽

Environmental Element ◽

Rainy Days

Tembakau temanggung banyak dibudidayakan pada daerah pegunungan, terutama di lereng Gunung Sum-bing dan Gunung Sindoro. Untuk mengetahui pengaruh ketinggian tempat terhadap produksi dan mutu tem-bakau temanggung maka dilakukan percobaan untuk mengetahui pengaruh faktor lingkungan terhadap pro-duksi dan mutu tembakau temanggung. Percobaan pot dilakukan di Kabupaten Temanggung-Jawa Tengah, pada bulan Maret–Agustus 2008 dengan 3 perlakuan lokasi tumbuh yang mempunyai perbedaan elevasi tempat, yakni (1) Desa Tlilir berelevasi 1395 m dpl, (2) Desa Wonotirto berelevasi 1245 m dpl, dan (3) Desa Sunggingsari berelevasi 880 m dpl dengan media tanah yang sama (seri Wonotirto). Perlakuan disusun da-lam rancangan tersarang dengan 9 ulangan, dimana ulangan tersarang dalam perlakuan. Hasil percobaan menunjukkan bahwa lokasi tumbuh mempengaruhi produksi dan kadar nikotin tembakau yang dihasilkan. Produksi rajangan kering tertinggi (28,3 g/tanaman) diperoleh dari tembakau yang ditanam di Desa Wono-tirto sedangkan kadar nikotin tertinggi (6,24%) diperoleh Desa Tlilir. Perbedaan lokasi tumbuh diikuti oleh perbedaan unsur-unsur lingkungan (temperatur udara, kelembapan udara relatif, curah hujan, dan jumlah hari hujan) selama masa hidup tanaman. Unsur lingkungan yang mempengaruhi produksi adalah temperatur udara, kelembapan relatif, curah hujan, dan jumlah hari hujan. Adapun unsur lingkungan yang mempenga-ruhi kadar nikotin adalah elevasi tempat, temperatur udara, dan kelembapan relatif. Temanggung tobacco is cultivated in highly areas, especially at Sumbing and Sindoro mountainside. To de-termine the effect of land elevation on yield and quality of temanggung tobacco, experiment had been con-ducted at different land elevation. Pot experiment was conducted in the Temanggung Regency-Central Java, on March–August 2008 with 3 treatments of growth location which has different site altitude, that is (1) Tlilir with site altitude 1395 m above sea level (asl), (2) Wonotirto with site altitude 1245 m asl, and (3) Sung-gingsari with site altitude 880 m asl with the same soil (Wonotirto series). The treatments were arranged in nested design with nine replications, which the replications were nested in the treatment. Result showed that growth location affect on yield and nicotine content. The highest production of dried sliced (28.3 g/ plant) was obtained in Wonotirto while the highest nicotine content (6.24%) was obtained in Tlilir. Differences in growth location followed by the difference of the environmental elements (air temperature, relative humi-dity, rainfall, and number of rainy days) during the lifetime of the plant. Environmental element that affect the production is the air temperature, relative humidity, rainfall, and number of rainy days. The environmen-tal elements that affect the nicotine content is the site altitude, air temperature, and relative humidity.

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THERMAL PERFORMANCE EVALUATION OF GREEN LIVING WALLS IN COMPOSITE CLIMATE

International Journal of Students Research in Technology & Management ◽

10.18510/ijsrtm.2020.842 ◽

2020 ◽

Vol 8 (4) ◽

pp. 8-16

Author(s):

Shruti Sharad Nagdeve ◽

Shweta Manchanda ◽

Anil Dewan

Keyword(s):

Relative Humidity ◽

Air Temperature ◽

Ambient Air ◽

Significant Drop ◽

Heat Gain ◽

Ambient Air Temperature ◽

High Solar Radiation ◽

The Difference ◽

Save Energy ◽

The Impact

Purpose of the study: Due to high solar radiation and extreme heat gain in composite climates, the envelope or the façade of the building becomes an essential part to modulate the heat transfer and temperature in the indoor environment. A passive sustainable approach to tackle heat gain is by adopting green living facades as the exterior skin. The objective of this research is to identify the potential of green living walls in modulating temperature and relative humidity in the composite climate of India. Methodology: This research is based on data collection in the form of a Case Study. The paper evaluates the difference of variation in temperature and relative humidity of two façade samples of the same building, one with a “green living facade” and one without it. Main Findings: The research aimed to justify that a green living facade may act as a passive strategy for composite climates. The result demonstrated that there is a significant temperature reduction between the ambient air temperature and indoor room temperature. The result also showed a notable change between ambient air temperature and the gap between the green living façade and the surface of the wall. Implications: Significant drop in indoor ambient temperature in composite climate may save energy for cooling or heating demands. Application of this study: This is a pilot study in order to carry out the main study for a similar application in order to categorize this as a passive sustainable façade strategy. Novelty/Originality of this study: The study is one of its kind attempt to investigate the impact of vertical green walls on thermal comfort in the composite climate of India.

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