A diagnostic study of flood producing rainstorm of September 1988 over northwest India with the aid of a fine mesh numerical analysis system

A numerical analysis of the synoptic situation leading to devastating floods in Punjab and adjoining states during September 1988 has been carried out. The analysis is done by three dimensional multivariate optimum interpolation (OI) scheme cast on 1° x 1° Lat./Long. Grid. Software has been developed for computation of several derived parameters and linked with the basic flow variable analysis. A diagnostic study of day-to-day rainfall versus the objectively analysed grid point fields of integrated horizontal flux divergence of water vapour is carried out, The study brings out a close spatial correspondence between the area of net moisture flux convergence on the analysis day and the area of heavy rainfall on the following day. The study suggests that the numerical analysis products can be of a good predictive value to a synoptic forecaster In heavy rainfall predictions under difficult and uncertain synoptic situations.

Urban Canyon in the CBD of Rio de Janeiro (Brazil): Thermal Profile of Avenida Rio Branco during Summer

This study aims to evaluate the thermal field of the central business district (CBD) of Rio de Janeiro during summer from land surface temperature (LST) and the thermal characteristics of the urban canopy layer (UCL) of the urban canyon in Avenida Rio Branco. In order to conduct this evaluation, two methods were employed: (1) TIRS Landsat-8 sensor for data selection and processing (latest generation, 2011–2020); (2) a field survey using nine sampling points—seven along two mobile transects, one fixed point, and one vertical measurement point, which required the use of an RPA (remotely piloted aircraft). Three categories of analysis were established for the field survey based on the prevailing synoptic situations: stability, instability, and post-instability. The CBD is characterized by extensive areas with surface heat islands, in which temperatures were higher than 38.9 °C; the areas with milder LSTs were Campo do Santana, Avenida Rio Branco, and one of the mixed-use zones (Praça Mauá). With respect to Rio Branco Avenue, the LST niches of lowest elevation were derived through building shadowing; however, due to the nature of the data, the orbital data diverged from the observation data of the 10 field-study days. In situ data revealed that the characteristics urban morphology of Avenida Rio Branco, by contrast with the LST result, is susceptible to the formation of atmospheric heat islands, presenting heat islands of very strong magnitude (over 6.1 °C) in atmospheric stability, strong magnitude (4.1–6.0 °C) in atmospheric instability, and moderate magnitude (2.1–4.0 °C) in post-atmospheric instability. Despite the synoptic situation, thermal cores were concentrated at 1 p.m. The intersection between Avenida Rio Branco, Rua do Ouvidor, and Praça Mauá stored most of the solar energy received during the day due to the greater sky obstruction caused by the verticalization. Finally, vertical analysis demonstrated the formation of a thermal inversion on the night of the highest mean air temperature (29.5 °C), probably due to the roughness and number of buildings in the urban canyon.

The course of birch pollen seasons in Sosnowiec (Southern Poland) in 1997–2020 in relation to meteorological conditions

The study's main objective was to specify the extent to which weather conditions were related to the course of birch pollen seasons in the years 1997–2020. The impact of atmospheric conditions on the daily concentrations of birch pollen grains, the Annual pollen integral (APIn), and the length of pollen seasons were studied. The dependency between each meteorological condition and various features of the birch pollen season was determined using Spearman’s rho correlation, the Kruskal–Wallis test, and cluster analysis with the k-means method. It has been shown that the duration of sunshine and average air temperature occurring within 14 days preceding the season has the most significant influence on the beginning of a birch pollen season. The value of daily birch pollen concentrations in Sosnowiec showed a statistically significant positive correlation with the duration of sunlight and the average and maximum wind speed. The daily concentration also depended on the synoptic situation: the mass airflow direction, the type of air mass inflow, and the type of weather front. The near-ground temperature influenced the APIn of birch pollen grains during the period of 14 days before the beginning of the season and the meteorological conditions occurring in the summer of the preceding year such as the maximum temperature, duration of sunlight, the maximum and average wind speed, and the relative air humidity. It was concluded that the length of birch pollen seasons decreased year by year.

Devastating tornado -of Kandi (9 April 1993) -A case study

A case study of the devastating tornado which occurred in Murshidabad district of West Bengal on 9 April 1993 is described, The synoptic situation and radar evidence in association with this tornado have been discussed. Also, how certain features of this tornado compared with some of tornadoes reported over West Bengal and attempt to provide an explanation regarding a burning sensation felt by people with passage of this tornado has been made.

QPF Model for lower Yamuna catchment, synoptic analogue method

The paper formulates a synoptic analogue model for issuing Quantitative Precipitation Forecast (QPF) for Lower Yamuna Catchment (LYC) based upon eleven years data (1998-2008) during southwest monsoon season. The results so derived were verified with realized Average Areal Precipitation (AAP) for the corresponding synoptic situation during 2009 southwest monsoon season. The performance of the model was observed Percentage Correct (PC) up to 86 % and for extreme events showed 100% correct with Heidke Skill Score (HSS) value 0.9. The experience during south west monsoon 2009 has shown that Synoptic analogue model can produce 24 hours advance QPF with accuracy and greater skill to facilitate the flood forecasters of Central Water Commission.

Characteristic of debris flow in the Kresna gorge on September 26, 2020

On September 26, 2021 a sudden debris flow in the northern part of the Kresna Gorge suspended traffic on the international road E-79. The following paper characterizes the synoptic situation that leads to a debris flow event and related deposits. The type of flow is determined bases on data obtained from grain size and morphoscopic analyses. A general assessment of the strengthening measures is made.

A diagnostic study of some flood producing rainfall events in Bangladesh with a limited area analysis-forecast system

Lkkj & bl ’kks/k&Ik= esa nf{k.kh if’peh ekulwu dh vof/k ds nkSjku caxykns’k esa Hkkjh o"kkZ ds dkj.k vkus okyh ck<+ dk uSnkfud v/;;u fd;k x;k gSA bl v/;;u dk eq[; mn~ns’; caxykns’k ds unh csfluksa ds m/oZ izokg okys Hkkxksa esa yxkrkj gksus okyh Hkkjh o"kkZ dh flukWfIVd fLFkfr;ksa dk irk yxkuk gS A o"kZ 1987 vkSj 1998 ds nkSjku gqbZ lcls vf/kd o"kkZ vkSj lcls vf/kd ck<+ okys nks o"kksZa dk Hkkjh o"kkZ okys rwQku ds laca/k esa v/;;u fd;k x;k gSA bZ- lh- ,e- MCY;w- ,Q- bZ- vkj- ,-&40 ls muds fQi lkbV ls MkmuyksM fd, x, uSnkfud fo’ys"k.k ds fy, ekSle laca/kh ekufp= rS;kj fd, x, gSaA y?kq vof/k esa o"kkZ dk izfr:i.k djus ds fy, ¶yksfjMk jkT; fo’ofo|ky; ds lhfer {ks= iwokZuqeku fun’kZ dk mi;ksx fd;k x;k gS A bl fun’kZ dks {kSfrt fxzM ij vk/kk fMxzh v{kka’k@ns’kkraj vkSj Å/okZ/kj esa 16 flxek Lrjksa ij O;kogkfjd cukus ds fy, iz;qDr fd;k x;k gSA v/;;u okys bu o"kksZa esa ck<+ ykus okys o"kkZ&rwQkuksa ds fy, mRrjnk;h lkekU; flukWfIVd fLFkfr] bu mRrjh caxykns’k esa mRrjkfHkeq[kh v{kka’k ij ekSleh ekulwu nzks.kh ds v{k dh vofLFkfr vkSj cM+s iSekus ij ifjlapj.k dh folaxfr;ksa ds izHkkoLo:Ik mi;qZDr fLFkfr;ksa esa fLFkj ikbZ xbZ gSA lhfer {ks= fun’kZ ls o"kkZ ds iwokZuqeku 24 ?kaVksa vkSj 48 ?kaVksa dh iwokZuqeku vof/k;ksa esa izkIr gq, gS tks izsf{kr o"kkZ forj.k ds laca/k esa lqlaxr ik, x, gSaA A diagnostic study of flood producing heavy rainfall in Bangladesh during the southwest monsoon period has been carried out. The study focuses on identifying the synoptic situations leading to persistent heavy rainfall within Bangladesh and in the upstream portions of the river basins of Bangladesh. Case studies are carried out in respect of heavy rainstorms in the two most outstanding excess rainfall and flood years 1987 and 1998. The weather maps for diagnostic analysis are prepared from ECMWF ERA-40 Reanalysis data sets downloaded from their ftp site. A limited area forecast model based on Florida State University has been used for simulating the precipitation in short range. The model has been customized to run on half degree Lat./Long. horizontal grid and 16 sigma levels in the vertical. The common synoptic situation responsible for flood producing rainstorms in the years examined is the positioning of the axis of seasonal monsoon trough in a northerly latitude over north Bangladesh and persistence of the above conditions under the influence of large scale circulation anomalies. The limited area model produced precipitation forecasts in 24h and 48h forecast ranges, which were reasonably well placed with reference to the observed rainfall distribution.

Heights of Cb clouds around Chhatrapati Shivaji International (C.S.I.) airport, Mumbai - Diurnal and seasonal variations

Lkkj & bl 'kks/k&i= esa 1990&99 ds o"kksZa ds nkSjku ekSle dk;kZy;] N=ifr f’kokth vUrjjk"Vªh; ¼lh- ,l- vkbZ-½ gokbZ vM~Ms esa ,df=r fd, x, jsMkj ds vk¡dM+ksa ds vk/kkj ij gokbZ vM~Ms ds lehi 200 fd- eh- dh ifjf/k esa 6 fd- eh- ls Åij vFkok blls vkSj vf/kd Å¡pkbZ ij QSys diklh es?kksa ¼lh- ch-½ dk v/;;u fd;k x;k gSA blesa lh- ch- lSyksa dh dqy la[;k ds ekSleh] ekfld vkSj ?kaVsokj forj.k vkSj mudh Å¡pkb;ksa] lh- ch- lfgr fnuksa dh la[;k] {kksHkeaMyh; lhek dh Å¡pkbZ rd igq¡pus okys lh- ch- lSyksa] foiqy lh- ch- es?kksa ds cuus ds izkFkfedrk okys LFkkuksa vkSj mudh xfr dh tk¡p djds mu ij fopkj&foe’kZ fd;k x;k gSA lh- ,l- vkbZ- gokbZ vM~Ms eqEcbZ ds lehi lh- ch- es?kksa ds fodkl ds fy, mÙkjnk;h flukfIVd fLFkfr;ksa dk Hkh irk yxk;k x;k gS vkSj mu ij fopkj&foe’kZ Hkh fd;k x;k gSA Based on radar data collected at the Meteorological Office, Chhatrapati Shivaji International (C.S.I.) airport, Mumbai during the years 1990-99, a study has been made on cumulonimbus (Cb) clouds with their height of top 6 km or more over an area having a radius of 200 km around the airport. The seasonal, monthly and hourly distribution of the total number of Cb cells and their heights, number of days with Cb, Cb cells that reached tropopause height, the preferred places of formation of large Cb clouds and their movement have been examined and discussed. The synoptic situation(s) responsible for the development of Cb clouds around C.S.I. airport, Mumbai have also been identified and discussed.

Urban Canyon in the CBD of Rio de Janeiro (Brazil): Thermal Profile of Avenida Rio Branco during Summer

This study aims to evaluate the land surface temperature (LST) and the thermal characteristics of the Urban Canopy Layer (UCL) of the urban canyon in Avenida Rio Branco in the Central Business District (CBD) of Rio de Janeiro during summer. In order to conduct this evaluation, two methods were employed: 1) TIRS Landsat-8 sensor for data selection and processing (latest generation, 2011-2020); ; 2) field survey using nine sampling points &mdash; seven along two mobile transects, one fixed point, and one vertical measurement point, which required the use of a RPA (Remotely Piloted Aircraft). Three categories of analysis were established for the field survey based on the prevailing synoptic situations: stability, instability, and post-instability. The CBD is characterized by extensive areas with surface heat islands, in which temperatures were higher than 38.9&deg;C; the areas with milder LSTs were Campo do Santana, Avenida Rio Branco, and one of the Mixed-Use Zones (Pra&ccedil;a Mau&aacute;). With respect to Rio Branco Avenue, the LST niches of lowest elevation were derived through building shadowing; however, the orbital data diverged from the observation data of the ten field-study days. In situ data revealed that the characteristics urban morphology of Avenida Rio Branco is susceptible to the formation of heat islands, presenting heat islands of very strong magnitude (over 6.1&deg;C) in atmospheric stability, strong magnitude (4.1-6.0&deg;C) in atmospheric instability, and moderate magnitude (2.1&deg;C-4.0&deg;C) in post-atmospheric instability. Despite the synoptic situation, thermal cores were concentrated at 1 pm. The intersection between Avenida Rio Branco, Rua do Ouvidor, and Pra&ccedil;a Mau&aacute; stored most of the solar energy received during the day due to the greater sky obstruction caused by the verticalization. Finally, vertical analysis demonstrated the formation of a thermal inversion on the night of the highest mean air temperature (29.5&deg;C), probably, due to the roughness and number of buildings in the urban canyon.

Effect of mature spruce forest on canopy interception in subalpine conditions during three growing seasons

The interception process in subalpine Norway spruce stands plays an important role in the distribution of throughfall. The natural mountain spruce forest where our measurements of throughfall and gross precipitation were carried out, is located on the tree line at an elevation of 1,420 m a.s.l. in the Western Tatra Mountains (Slovakia, Central Europe). This paper presents an evaluation of the interception process in a natural mature spruce stand during the growing season from May to October in 2018–2020. We also analyzed the daily precipitation events within each growing season and assigned to them individual synoptic types. The amount and distribution of precipitation during the growing season plays an important role in the precipitation-interception process, which confirming the evaluation of individual synoptic situations. During the monitored growing seasons, precipitation was normal (2018), sub-normal (2019) and above-normal (2020) in comparison with long-term precipitation (1988–2017). We recorded the highest precipitation in the normal and above-normal precipitation years during the north-eastern cyclonic synoptic situation (NEc). During these two periods, interception showed the lowest values in the dripping zone at the crown periphery, while in the precipitation sub-normal period (2019), the lowest interception was reached by the canopy gap. In the central crown zone near the stem, interception reached the highest value in each growing season. In the evaluated vegetation periods, interception reached values in the range of 19.6–24.1% of gross precipitation total in the canopy gap, 8.3–22.2% in the dripping zone at the crown periphery and 45.7–51.6% in the central crown zone near the stem. These regimes are expected to change in the Western Tatra Mts., as they have been affected by windstorms and insect outbreaks in recent decades. Under disturbance regimes, changes in interception as well as vegetation, at least for some period of time, are unavoidable.