Identification of key parameters producing rainfall

o"kkZ ds eq[; izkpyksa dk irk yxkus ds fy, bl 'kks/k i= ls 'kks/kdrkZvksa us m".kdfVca/kh; o"kkZ ekiu fe’ku ¼Vh- vkj- ,e- ,e-½ mixzg vk¡dM+k vk/kkj dh tk¡p dh gSA bl rF; dks le>us ds mijkUr fd c<+us okys ok;q iklZy ds }kjk ikuh ds ok"ihdj.k] ok"i ds la?kuu vkSj m"ek ÅtkZ ds laogu ls es?k cursa gS vkSj o"kkZ gksrh gSA 'kks/kdrkZvksa us ok;qeaMy dh fofHkUu Å¡pkbZ;ksa ij o"kkZ izfØ;k ds eq[; lg;ksfx;ksa ds :i esa es?k nzo ty ¼lh-,y-MCY;w-½] o"kZ.k ty ¼ih-MCY;w-½ rFkk xqIr m"ek ¼,y-,p-½ ds ckjs esa tkudkjh izkIr djuh vkjaHk dj nh gSSA bu vk¡dM+ksa dks cgq lekJ;.k fun’kZ esa Mkyk x;k gSA ;g ik;k x;k gSS fd o"kkZ vkSj bu izkpyksa esa egRoiw.kZ lglaca/k gSA blls LFkkfir gq, dk;kZRed laca/kksa ls fdlh Hkh le; o"kkZ dk vkdyu fd;k tk ldrk gS c’krZs dkWyeuj lh-,y-MCY;w-] ih-MCY;w- vkSj ,y-,p- eku miyC?k gksaA ,d ;k nks ds LFkku ij bu lHkh rhuksa izkpyksa dks cgq lekJ;.k fun’kZ esa 'kkfey djus ds QyLo:i o"kkZ dk csgrj iwokZuqeku yxk;k tk ldk gSA lh- ,y- MCY;w-] ,y- ,p- vkSj ih- MCY;w- ds chp egRoiw.kZ lglaca/k gSaA In search of the key parameters causing rainfall, the authors have explored Tropical Rainfall Measuring Mission (TRMM) satellite data base. By realizing the fact that evaporation of water, condensation of vapour and transport of heat energy by a rising air parcel are all about formation of cloud and rain, the authors have started their quest considering cloud liquid water (CLW), precipitation water (PW) and latent heat (LH) at different altitudes of the atmosphere as major contributors to rainfall mechanism. These data have been fitted to multiple regressions. It is found that significant correlations exist between rainfall and these parameters. The functional relationships so established are able to estimate surface rainfall at any instant, provided columnar CLW, PW and LH values are available. Inclusion of all the three parameters in multiple regression leads to better predictability of rainfall, instead of one or two. Significant correlations exist between CLW, LH and PW.

Mapping the Spatiotemporal Diversity of Precipitation in Iran

Despite located in a semi-arid and arid part of the world, Iran enjoys a very diverse climate. As a result, water availability in different regions of the country is in a veil of ambiguity. To have a better insight, we investigate the spatiotemporal diversity of precipitation over the country by analyzing the 33-years long monthly precipitation time series (1983-2016) at 461 measuring rain-gauge stations. Cluster Analysis (CA) both hierarchical and non-hierarchical clustering approaches and Principal Component Analysis (PCA) was used to determine the homogeneous precipitation zones at three macro, meso, and micro-scales. First, the country is divided into six precipitation macro-regions using CA. Each region shows a unique mean annual hyetograph and is influenced by a particular air moisture mass entering the country. Then, the six regions were divided into 10 regions of meso-resolution through Hierarchical clustering (HC) and K-Means Clustering. Finally, an optimal number of 24 micro-zones is established that reflect a comprehensive precipitation map over the country, employing PCA, Hierarchical clustering, and K-Means Clustering. The annual hyetograph of each zone showed a unique pattern and distribution with a varying magnitude of monthly precipitation compared to others. The long-term (i.e., 33-years) mean annual rainfall in each region and zone is calculated, and the monthly and annual-precipitation water availability in the country is estimated. The result gives an accurate insight into the amount of precipitation that is expected to fall in each zone during each month of the year, that may be used as the reference for the prediction of the dry and wet seasons and years and also for the allocation of the harvested precipitation water to different consumptive sectors. The result shows that the Hierarchical clustering and PCA have significant classification performance in meso and micro- climatological zoning. Also, it was observed that there are significant similarities between the PCA and Hierarchical clustering (Ward’s method-Pearson correlation) results in micro-climatological zoning.

Linear relationship between effective radius and precipitation water content near the top of convective clouds: measurement results from ACRIDICON–CHUVA campaign

Quantifying the precipitation within clouds is a crucial challenge to improve our current understanding of the Earth's hydrological cycle. We have investigated the relationship between the effective radius of droplets and ice particles (re) and precipitation water content (PWC) measured by cloud probes near the top of growing convective cumuli. The data for this study were collected during the ACRIDICON–CHUVA campaign on the HALO research aircraft in clean and polluted conditions over the Amazon Basin and over the western tropical Atlantic in September 2014. Our results indicate a threshold of re∼13 µm for warm rain initiation in convective clouds, which is in agreement with previous studies. In clouds over the Atlantic Ocean, warm rain starts at smaller re, likely linked to the enhancement of coalescence of drops formed on giant cloud condensation nuclei. In cloud passes where precipitation starts as ice hydrometeors, the threshold of re is also shifted to values smaller than 13 µm when coalescence processes are suppressed and precipitating particles are formed by accretion. We found a statistically significant linear relationship between PWC and re for measurements at cloud tops, with a correlation coefficient of ∼0.94. The tight relationship between re and PWC was established only when particles with sizes large enough to precipitate (drizzle and raindrops) are included in calculating re. Our results emphasize for the first time that re is a key parameter to determine both initiation and amount of precipitation at the top of convective clouds.

Assessment of the Current and Projected Conditions of Water Availability in the Sevastopol Region for Grape Growing

Viticulture is a sector very sensitive to climate change. Observed and expected changes in temperature and precipitation can change the conditions necessary for viticulture in a particular area or make these conditions totally unsuitable for viticulture. Precipitation (water availability) and air temperature are the key meteorological parameters regulating the quality of grapes and wine. We used an ensemble of model data from the CMIP6 project to evaluate all possible changes in water availability in the area around Sevastopol by the middle and the end of the 21st century for two Shared Socioeconomic Pathway scenarios (SSP2-4.5 and SSP5-8.5). The hydrothermal coefficient and dryness index have been used to evaluate the water availability. The results have shown that, based on the indices values, viticulture in the study region will be possible without irrigation, but, at the same time, the vines may experience a certain level of dryness.

The value of water isotope data on improving process understanding in a glacierized catchment on the Tibetan Plateau

This study integrated a water isotope module into the hydrological model THREW (Tsinghua Representative Elementary Watershed) which has been successfully used in high and cold regions. Signatures of oxygen stable isotope (18O) of different water inputs and stores were simulated coupling with the simulations of runoff generation. Isotope measurements of precipitation water samples and assumed constant isotope signature of ice meltwater were used to force the isotope module. Isotope signatures of water stores such as snowpack and subsurface water were updated by an assumed completely mixing procedure. Fractionation effects of snowmelt and evapotranspiration were modeled in a Rayleigh fractionation approach. The isotope-aided model was subsequently applied for the quantification of runoff components and estimations of mean water travel time (MTT) and mean residence time (MRT) in the glacierized watershed of Karuxung river on the Tibetan Plateau. Model parameters were calibrated by three variants with different combinations of streamflow, snow cover area and isotopic composition of stream water. Modeled MTT and MRT were validated by estimates of a tracer-based sine-wave method. Results indicate that (1) the proposed model performs well on simultaneously reproducing the observations of streamflow, snow cover area and isotopic composition of stream water, despite the fact that only precipitation water samples were available for tracer input; (2) isotope data facilitate more robust estimations on contributions of runoff components (CRCs) to streamflow in the melting season, as well as on MTT and MRT; (3) involving isotope data for the model calibration obviously reduces uncertainties in the quantification of CRCs and estimations of MTT and MRT, through better constraining the competitions among different runoff processes induced by meltwater and rainfall. Our results inform scientists on the high value of water isotope data for improving process understanding in a glacierized basin on the Tibetan Plateau.

THE EFFICIENCY OF USING CAM MECHANISMS TO OPERATE THE EQUIPMENT FOR OPENING AND INTERRUPTING WATERING FURROWS

Due to climate change, there have been changes in temperature, distribution and precipitation, phenomena that have led to the development of technologies that increase the efficiency of precipitation water use and support the preservation of soil quality. The paper presents some theoretical considerations on the cam mechanisms for actuating the working parts the equipment for opening and interrupting watering furrows are provided with; setting the optimal dimensions of the blades of the equipment for furrow opening through the experiments performed is also made. By using the cam mechanisms in the equipment for opening and interrupting watering furrows both superior quality indices in the execution of the work but also a quiet operation of the equipment are obtained and by optimizing the size of the working part, the volume of water accumulated between furrows increases significantly.

Linear relationship between effective radius and precipitation water content near the top of convective clouds

Quantifying the precipitation within clouds is a crucial challenge to improve our current understanding of the Earth’s hydrological cycle. We have investigated the relationship between the effective radius of droplets and ice particles (re) and precipitation water content (PWC) measured by cloud probes near the top of growing convective cumuli. The data for this study were collected by aircraft measurements in clean and polluted conditions over the Amazon Basin and over the western tropical Atlantic in September 2014. Our results indicate a threshold of re ∼ 13 μm for warm rain initiation in convective clouds, which is in agreement with previous studies. In clouds over the Atlantic Ocean, warm rain starts at smaller re, likely linked to the enhancement of coalescence of drops formed on giant cloud condensation nuclei. In cloud passes where precipitation starts as ice hydrometeors, the threshold of re is also shifted to values smaller than 13 μm when coalescence processes are suppressed and precipitating particles are formed by accretion. We found a statistically significant linear relationship between PWC and re for measurements at cloud tops, with a correlation coefficient of ∼0.94. The tight relationship between re and PWC was established only when particles with sizes large enough to precipitate (drizzle and raindrops) are included in calculating re. Our results emphasize for the first time that re is a key parameter to determine both initiation and amount of precipitation at the top of convective clouds.

The value of water isotope data on improving process understanding in a glacierized catchment on the Tibetan Plateau

This study integrated a water isotope module into the hydrological model THREW which has been successfully used in high and cold regions. Signatures of oxygen stable isotope (18O) of different water inputs and stores were simulated coupling with the simulations of runoff generations. Isotope measurements of precipitation water samples and global precipitation isotope product, as well as assumed constant isotope signature of ice meltwater were used to force the isotope module. Isotope signatures of water stores such as snowpack and subsurface water were updated by an assumed completely mixing procedure. Fractionation effects of snowmelt and evapotranspiration were modeled in a Rayleigh fractionation approach. The isotope-aided model was subsequently applied for the quantifications of runoff components and estimations of mean water travel time (MTT) and mean residence time (MRT) in the glacierized watershed of Karuxung River on the Tibetan Plateau. Model parameters were constrained by three different combinations of observations including a single-objective calibration using streamflow measurement solely, a dual- objective calibration using both streamflow measurement and MODIS estimated snow cover area, and a triple- objective calibration using additionally isotopic composition of stream water. Modeled MTT and MRT was validated by estimate of a tracer-based sine-wave method. Results indicate that: (1) the proposed model performed quite well on simultaneously reproducing the observations of streamflow, snow cover area, and isotopic composition of stream water, despite that only precipitation water samples were available for tracer input; (2) isotope data helped to estimate more plausible contributions of runoff components (CRCs) to streamflow in the melting season, and improved the robustness of MTT and MRT estimations; (3) involving isotope data for the model calibration obviously reduced uncertainties of the quantification of CRCs and estimations of MTT and MRT, through better constraining the strong competitions among different runoff processes induced by meltwater and rainfall. Our results inform high value of water isotope data on improving process understanding in a glacierized basin on the Tibetan Plateau.