Control of the Dust Vertical Distribution over Western Africa by Convection and Scavenging

Saharan dust represents more than 50%of the total desert dust emitted around the globe and its radiative effect significantly affects the atmospheric circulation at a continental scale.Previous studies on dust vertical distribution and the Saharan Air Layer(SAL)showed some shortcomings that could be attributed to imperfect representation of the effects of deep convection and scavenging.The authors investigate here the role of deep convective transport and scavenging on the vertical distribution of mineral dust over Western Africa.Using multi-year(2006-2010)simulations performed with the variable-resolution(zoomed)version of the LMDZ climate model.Simulations are compared with aerosol amounts recorded by the Aerosol Robotic Network(AERONET)and with vertical profiles of the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP)measurements.LMDZ allows a thorough examination of the respective roles of deep convective transport,convective and stratiform scavenging,boundary layer transport,and advection processes on the vertical mineral dust distribution over Western Africa.The comparison of simulated dust Aerosol Optical Depth(AOD)and distribution with measurements suggest that scavenging in deep convection and subsequent re-evaporation of dusty rainfall in the lower troposphere are critical processes for explaining the vertical distribution of desert dust.These processes play a key role in maintaining a well-defined dust layer with a sharp transition at the top of the SAL and in establishing the seasonal cycle of dust distribution.This vertical distribution is further reshaped offshore in the Inter-Tropical Convergence Zone(ITCZ)over the Atlantic Ocean by marine boundary layer turbulent and convective transport and wet deposition at the surface.

Some Features of Black Carbon Aerosols Connected with Regional Climate Over Pristine Environment

The authors report the results of aethalometer black carbon(BC)aerosol measurements carried out over a rural(pristine)site,Panchgaon,Haryana State,India during the winter months of 2021-2022 and 2022-2023.They are compared with collocated and concurrent observations from the Air Quality Monitoring Station(AQMS),which provides synchronous air pollution and surface meteorological parameters.Secular variations in BC mass concentration are studied and explained with variations in local meteorological parameters.The biomass burning fire count retrievals from NASA-NOAA VIIRS satellite,and backward airmass trajectories from NOAA-ERL HYSPLIT Model analysis have also been utilized to explain the findings.They reveal that the north-west Indian region contributes maximum to the BC mass concentration over the study site during the study period.Moreover,the observed BC mass concentrations corroborate the synchronous fire count,primary and secondary pollutant concentrations.The results were found to aid the development of mitigation methods to achieve a sustainable climate system.

Evaluation of the Mechanisms Acting on the Atlantic Meridional Overturning Circulation in CESM2 for the 1pctCO_(2) Experiment

The Atlantic Meridional Overturning Circulation(AMOC)is a crucial component of the Earth’s climate system due to its fundamental role in heat distribution,carbon and oxygen transport,and the weather.Other climate components,such as the atmosphere and sea ice,influence the AMOC.Evaluating the physical mechanisms of those interactions is paramount to increasing knowledge about AMOC’s functioning.In this study,the authors used outputs from the Community Earth System Model version 2 and observational data to investigate changes in theAMOC and the associated physical processes.Two DECK experiments were evaluated:piControl and 1pctCO_(2),with an annual increase of 1%of atmospheric CO_(2).The analysis revealed a significant decrease in the AMOC,associated with changes in mixed layer depth and buoyancy in high latitudes of the North Atlantic,resulting in the shutdown of deep convection and potentially affecting the formation of North Atlantic Deep Water and Antarctic Bottom Water.A vital aspect observed in this study is the association between increased runoff and reduced water evaporation,giving rise to a positive feedback process.Consequently,the rates of freshwater spreading have intensified during this period,which could lead to an accelerated disruption of the AMOC beyond the projections of existing models.

Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation

The Intertropical Convergence Zone(ITCZ)is a key atmospheric system on a global scale,primarily driven by trade wind convergence near the equator.The ITCZ plays a crucial role in modulating the climate of the borders of tropical continental areas.For instance,Northeastern Brazil experiences a climate influenced by the ITCZ over the Atlantic Ocean.In some periods,the ITCZ exhibits double bands,known as the double ITCZ.While the features of the ITCZ have been described using various approaches and atmospheric variables,there is still a lack of regional studies focusing on the ITCZ and double ITCZ in the Atlantic Ocean.In this context,the main goals of this study are(1)to describe a simple algorithm based on precipitation to identify the ITCZ and double ITCZ,(2)to present a climatology(1997-2022)of the position,width,and intensity of these two convective bands,and(3)to investigate variabilities in the ITCZ characteristics associated with anomalies of sea surface temperature(SST)in the tropical Pacific and Atlantic oceans.The double ITCZ typically occurs southward of the main cloud band,and between February and April,both bands are more distant(~4.5°).In the western sector of the Atlantic Ocean,the ITCZ and its double band extend to more southerly latitudes in austral autumn.Considering the entire Atlantic basin,the annual mean of the latitudinal position,width,and intensity of the ITCZ is 4.9°N,4.2°,and 11 mm/day,respectively,while for the double ITCZ,it is 0.4°N,2.6°,10.3 mm/day,respectively.While the SST anomalies in the Pacific Ocean(El Niño and La Niña episodes)affect more the ITCZ width,the SST anomalies in the Tropical South Atlantic affect both its position and width.

Seasonal Variability of Rainfall and Thunderstorm Patterns in Kenya

This paper presents an analysis of spatial and temporal variation of rainfall and thunderstorm occurrence over Ken-ya from January 1987 to December 2017.The meteorological data used were obtained from the Kenya Meteorological Department(KMD)for the same period.This included the monthly thunderstorm occurrences and rainfall amounts of 26 synoptic stations across the country.The characteristics of monthly,seasonal and annual frequency results were presented on spatial maps while Time series graphs were used to display the pattern for annual cycle,seasonal varia-tions and the inter-annual variability of rainfall amounts and thunderstorm occurrences.A well-known non-parametric statistical method Mann Kendall(MK)trend test was used to determine and compare the statistical significance of the trends.Thunderstorm frequencies over the Eastern,Central and Coast regions of the country showed a bimodal pattern with high frequencies coinciding with March-April-May(MAM)and October-November-December(OND)rainy sea-sons.Very few thunderstorm days were detected over June-July-August(JJA)season.The areas to the western part of the country,near Lake Victoria,had the highest thunderstorm frequencies in the country over the three seasons:MAM,JJAS and OND.The annual frequency showed a quasi-unimodal pattern.These places near Lake Victoria showed sig-nificantly increasing thunderstorm trends during the MAM and OND seasons irrespective of the rainfall trends.This shows the effects of Lake Victoria over these areas,and it acts as a continuous source of moisture for thunderstorm for-mation.However,most stations across the country showed a reducing trend of thunderstorm frequency during MAM and JJA seasons.The importance of these findings is that they could support various policy makers,and users of cli-mate information,especially in the agriculture and aviation industries.

Multi-decadal Changes of the Impact of El Niño Events on Tibetan Plateau Summer Precipitation

Precipitation on the Tibetan Plateau(TP)has an important effect on the water supply and demand of the downstream population.Involving recent climate change,the multi-decadal variations of the impact of El Niño-Southern Oscillation(ENSO)events on regional climate were observed.In this work,the authors investigated the changes in summer precipitation over TP during 1950-2019.At the multi-decadal scale,the authors found that the inhabiting impact of El Niño events on the TP summer precipitation has strengthened since the late 1970s.The main factor contributing to this phenomenon is the significant amplification in the decadal amplitude of El Niño during 1978-2019 accompanied by a discernible escalation in the frequency of El Niño events.This phenomenon induces anomalous perturbations in sea surface temperatures(SST)within the tropical Indo-Pacific region,consequently weakening the atmospheric vapor transport from the western Pacific to the TP.Additionally,conspicuous anomalies in subsidence motion are observed longitudinally and latitudinally across the TP which significantly contributes to a curtailed supply of atmospheric moisture.These results bear profound implications for the multi-decadal prediction of the TP climate.

Analysis of Extreme Temperature Variability in Rwanda

The temperature is one of the most important factors in weather and climate forecasting.Studying its behaviour is crucial to understanding climate variability,which could vary spatially and temporally at local,regional,and global scales.Several recent studies on air temperature findings show that the Earth’s near surface air temperature increased between 0.6℃ and 0.8℃ throughout the twentieth century.Using temperature records from ten meteorological stations,this study examined climate variability in Rwanda from the 1930s to 2014.The air temperature data were collected from Meteo Rwanda.Before making the analysis,the authors used software,such as Excel 2007 and INSTAT to control the quality of the raw data.The analysis of maxima and minima indicated that the trends of maximum air temperature were positive and significant at height meteorological stations,whereas the trends for minimum air temperature were found to be at 10 meteorological stations.For all parameters analysed,Kigali Airport meteorological station indicated the higher significance of the trends.The majority of meteorological stations showed an increase in both hot days and nights,confirming Rwanda’s warming over time.The analysis of average seasonal air temperature showed almost similar trends even though not all were significant.This similarity in trends could be attributed to the fact that Rwanda’s short and long dry seasons coincide with rainy seasons.

Wavelet Analysis of Average

The identification method in the CurveExpert-1.40 software environment revealed asymmetric wavelets of changes in the average monthly temperature of New Delhi from 1931 to 2021.The maximum increment for 80 years of the average monthly temperature of 5.1℃was in March 2010.An analysis of the wave patterns of the dynamics of the average monthly temperature up to 2110 was carried out.For forecasting,formulas were adopted containing four components,among which the second component is the critical heat wave of India.The first component is the Mandelbrot law(in physics).It shows the natural trend of decreasing temperature.The second component increases according to the critical law.The third component with a correlation coefficient of 0.9522 has an annual fluctuation cycle.The fourth component with a semi-annual cycle shows the influence of vegetation cover.The warming level of 2010 will repeat again in 2035-2040.From 2040 the temperature will rise steadily.June is the hottest month.At the same time,the maximum temperature of 35.1℃in 2010 in June will again reach by 2076.But according to the second component of the heat wave,the temperature will rise from 0.54℃to 16.29°C.The annual and semi-annual cycles had an insignificant effect on the June temperature dynamics.Thus,the identification method on the example of meteorological observations in New Delhi made it possible to obtain summary models containing a different number of components.The temperature at a height of 2 m is insufficient.On the surface,according to space measurements,the temperature reaches 55°C.As a result,in order to identify more accurate asymmetric wavelets for forecasting,the results of satellite measurements of the surface temperature of India at various geographical locations of meteorological stations are additionally required.

Assessing the Impact of Gas Flaring and Carbon Dioxide Emissions on Precipitation Patterns in the Niger Delta Region of Nigeria Using Geospatial Analysis

This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average mean precipitation data sourced from CHRS at the University of Arizona and carbon dioxide emissions data from NASA’s AIRS in Giovanni,spanning from July 2002 to November 2011.To carry out the analysis,ArcGIS 5.0 and SPSS 25,employing Inverse Distance Weighting(IDW),were employed to assess CO_(2) emissions and rainfall for both November and July during the period from 2002 to 2011.Over the course of this study,it was observed that CO_(2) emission exhibited an upward trend,increasing from 327.5226 parts per million(ppm)in July 2002 to 390.0077 ppm in November 2011.Simultaneously,the rainfall demonstrated an increase,rising from 56.66 millimeters to 390.78 millimeters for both July and November from 2002 to 2011.Noteworthy findings emerged from the correlation analysis conducted.Specifically,from July 2000 to 2011,there was a weak positive correlation(0.3858)observed between CO_(2) emissions and minimum rainfall,while a strong negative correlation(–0.7998)was identified for maximum rainfall values.In November,both minimum and maximum CO_(2) emissions displayed strong negative correlations with rainfall,with coefficients of–0.8255 and–0.7415,respectively.These findings hold significant implications for comprehending the environmental dynamics within the Niger Delta.Policymakers and stakeholders can leverage this knowledge to formulate targeted strategies aimed at mitigating CO_(2) emissions and addressing potential climate change-induced alterations in rainfall patterns.

Global Effect of Climate Change on Seasonal Cycles,Vector Population and Rising Challenges of Communicable Diseases:A Review

This article explains ongoing changes in global climate and their effect on the resurgence of vector and pathogen populations in various parts of the world.Today,major prevailing changes are the elevation of global temperature and accidental torrent rains,floods,droughts,and loss of productivity and food commodities.Due to the increase in water surface area and the longer presence of flood water,the breeding of insect vectors becomes very high;it is responsible for the emergence and re-emergence of so many communicable diseases.Due to the development of resistance to chemicals in insect pests,and pathogens and lack of control measures,communicable zoonotic diseases are remerging with high infectivity and mortality.This condition is becoming more alarming as the climate is favoring pathogen-host interactions and vector populations.Rapid changes seen in meteorology are promoting an unmanageable array of vector-borne infectious diseases,such as malaria,Japanese encephalitis,filarial,dengue,and leishmaniasis.Similarly,due to unhygienic conditions,poor sanitation,and infected ground and surface water outbreak of enteric infections such as cholera,vibriosis,and rotavirus is seen on the rise.In addition,parasitic infection ascariasis,fasciolosis,schistosomiasis,and dysentery cases are increasing.Today climate change is a major issue and challenge that needs timely quick solutions.Climate change is imposing non-adaptive forced human migration territorial conflicts,decreasing ecosystem productivity,disease outbreaks,and impelling unequal resource utilization.Rapid climate changes,parasites,pathogens,and vector populations are on the rise,which is making great threats to global health and the environment.This article highlighted the necessity to develop new strategies and control measures to cut down rising vector and pathogen populations in endemic areas.For finding quick solutions educational awareness,technology up-gradation,new vaccines,and safety measures have to be adopted to break the cycle of dreadful communicable diseases shortly.

The Possibilities of Using the Minimax Method to Diagnose the State of the Atmosphere

The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works-the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air.Within the framework of this study,the task of probabilistic forecasting of diagnostic parameters and their combinations,leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere,was carried out.It is this state that,as shown by previous studies,a priori contribution to the development of a number of weather phenomena dangerous for society(squalls,hail,heavy rains,etc.).The results of applying the minimax method made it possible to identify a number of parameters,such as the intensity of circulation,the activity of the Earth’s magnetosphere,and the components of the geostrophic wind velocity,the combination of which led to the development of instability.In the future,it is possible to further expand the number of diagnosed parameters to identify more sensitive elements.In this sense,the minimax method,the usefulness of which is shown in this study,can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.

Snowfall Shift and Precipitation Variability over Sikkim Himalaya Attributed to Elevation-Dependent Warming

Sikkim Himalaya hosts critical water resources such as glacial,rain,and snow-fed springs and lakes.Climate change is adversely affecting these resources in various ways,and elevation-dependent warming is prominent among them.This study is a discussion of the elevation-dependent warming(EDW),snowfall shift,and precipitation variability over Sikkim Himalaya using a high-resolution ERA5-land dataset.Furthermore,the findings show that the Sikkim Himalaya region is experiencing a warming trend from south to north.The majority of the Sikkim Himalayan region shows a declining trend in snowfall.A positive advancement in snowfall trend(at a rate of 1 mm per decade)has been noticed above 4500 meters.The S/P ratio indicates a shift in snowfall patterns,moving from lower elevations to much higher regions.This suggests that snowfall has also transitioned from Lachung and Lachen(3600 m)to higher elevated areas.Moreover,the seasonal shifting of snowfall in the recent decade is seen from January-March(JFM)to February-April(FMA).Subsequently,the preceding 21 years are being marked by a significant spatiotemporal change in temperature,precipitation,and snowfall.The potent negative correlation coefficient between temperature and snowfall(–0.9),temperature and S/P ratio(–0.5)suggested the changing nature of snowfall from solid to liquid,which further resulted in increased lower elevation precipitation.The entire Sikkim region is transitioning from a cold-dry to a warm-wet weather pattern.In the climate change scenario,a drop in the S/P ratio with altitude will continue to explain the rise in temperature over mountainous regions.

Problems and Opportunities for Biometeorological Assessment of Conditions in Cold Season

The article is devoted to a discussion of the possibilities of biometeorological assessment of the severity of weather conditions during the cold season.The relevance of the study is ensured not only by the fact that residents of a number of states,whose total number is more than 27 million people,live in these extreme climatic conditions,but also by the need to improve biometeorological approaches to assessing the impact of these conditions on the body and health of the population.This study examined biometeorological characteristics that illustrate a measure of cold stress.These include the Siple wind-chill index;Bodman winter severity index;Arnoldi weather hardness coefficient;Mountain wind chill index;weather hardness coefficient according to I.M.Osokin.The results of a comparison of winter severity assessments based on the values of the calculated Siple and Bodman indices made it possible to establish that the Bodman index is more acceptable when assessing mildly severe winters.The most adequate for assessing the“severity”of the cold period against the background of a decrease in air temperature and an increase in wind speed is the Siple index.The need to provide the countries of the world with high-quality hydrometeorological and biometeorological forecast information is justified and relevant.In this regard,these studies are very promising.

Case Study of Coastal Fog Events in Senegal Using LIDAR Ceilometer

This study aims to examine the atmospheric conditions characterising fog phenomena on the Senegalese coast focusing on two specific instances that occurred on April 3 and April 30,2023.These events were detected by the LIDAR Ceilometer installed at LPAOSF/ESP/UCAD and confirmed on the METARs of the meteorological stations at Dakar and Diass airports.The LIDAR’s backscatter signal showed that the fog of April 3 started around midnight with a vertical extension at 100 m altitude and dissipated around 10 a.m.The April 30 event characterized by a good vertical extension from the surface up to 300 m above sea level,was triggered just after 2 a.m.and lasted around 3 hours.The results showed that a decrease in temperature,accompanied by an increase in humidity and light wind,is favorable for the triggering and persistence of fog.Sea Level Pressure(SLP)anomaly fields show two distinct configurations.The April 3 event was characterized by a zonal dipole of SLP anomalies between the Sahara and the northern Senegalese coast,while the April 30 event was characterized by a meridional dipole between the Sahara and the Gulf of Guinea area as far as the equatorial Atlantic.A weakening of the pressure around the study area was observed in both cases,allowing moisture advection to favor the onset of fog.The hovmoller diagrams of relative humidity and wind show that a good vertical extension of humidity associated with a westerly wind in the lower layers plays an important role in the formation and persistence of fog.The presence of dry air associated with a weak easterly wind in the middle layers could explain the low vertical extension of the fog on April 3.A strong wind in the lower layers would be responsible for the premature dissipation of the April 30 fog.

Investigating the Effects of Madden-Julian Oscillation on Climate Elements of Iran (1980-2020)

The Madden-Julian Oscillation is one of the large-scale climate change patterns in the maritime tropics,with sub-seasonal time periods of 30 to 60 days affecting tropical and subtropical regions.This phenomenon can cause changes in various quantities of the atmosphere and ocean,such as pressure,sea surface temperature,and the rate of evaporation from the ocean surface in tropical regions.In this research,the effects of Madden-Julian fluctuation on the weather elements of Iran have been investigated with the aim of knowing the effects of different phases in order to improve the quality of forecasts and benefits in territorial planning.At first,the daily rainfall data of 1980-2020 were received from the National Meteorological Organization and quality controlled.Using the Wheeler and Hendon method,the two main components RMM1 and RMM2 were analyzed,based on which the amplitude of the above two components is considered as the main indicator of the intensity and weakness of this fluctuation.This index is based on the experimental orthogonal functions of the meteorological fields,including the average wind levels of 850 and 200 hectopascals and outgoing long wave radiation(OLR)between the latitudes of 20 degrees south and 20 degrees north.The clustering of the 7-day sequence with a component above 1 was used as the basis for clustering all eight phases,and by calculating the abnormality of each phase compared to its long term in the DJF time frame,the zoning of each phase was produced separately.In the end,phases 1,2,7,8 were concluded as effective phases in Iran’s rainfall and phases 3,4,5,6 as suppressive phases of Iran’s rainfall.

Formation and Transport of a Saharan Dust Plume in Early Summer

This research studies the capability of the Weather Research and Forecasting model coupled with the Chemistry/Aerosol module(WRF-Chem)with and without parametrization to reproduce a dust storm,which was held on 27th June 2018 over Sahara region.The authors use satellite observations and ground-based measurements to evaluate the WRF-Chem simulations.The sensitivities of WRF-Chem Model are tested on the replication of haboob features with a tuned GOCART aerosol module.Comparisons of simulations with satellite and ground-based observations show that WRF-Chem is able to reproduce the Aerosol Optical Depth(AOD)distribution and associated changes of haboob in the meteorological fields with temperature drops of about 9℃and wind gust 20 m·s–1.The WRF-Chem Convec-tion-permitting model(CPM)shows strong 10-meter winds induced a large dust emission along the leading edge of a convective cold pool(LECCP).The CPM indicates heavy dust transported over the West African coast(16°W-10°W;6°N-21°N)which has a potential for long-distance travel on 27th June between 1100 UTC and 1500 UTC.The daily precipitation is improved in the CPM with a spatial distribution similar to the GPM-IMERG precipitation and maxi-mum rainfall located at the right place.As well as raising a large amount of dust,the haboob caused considerable dam-age along its route.

Ionospheric Currents in the Equatorial and Low Latitudes of Africa

The magnetometer data obtained for 2008 from geomagnetic stations installed across Africa by magnetic data acquisition set (MAGDAS) have been used to study the ionospheric Sq current system in the equatorial and low-latitudes of Africa. The aim of this work is to separate the quiet-day field variations obtained in the equatorial and low latitude regions of Africa into their external and internal field contributions and then to use the paired external and internal coefficients of the SHA to determine the source current and induced currents. The method used involved a spherical harmonic analysis (SHA). This was applied in the separation of the internal and external field/current contribution to the Sq variations. The result shows that the variation in the currents is seen to be a dawn-to-dusk phenomenon with the variation in the external currents different from that of the internal currents both in amplitude and in phase. Furthermore, the seasonal variation in the external current maximizes during the March equinox and minimizes during the December solstice. The maximum current observed in AAB and ILR is due to the Equatorial Electrojet Current present in the AAB and ILR stations. Seasonal variation was observed in the geomagnetic component variations as well as in the currents. This is attributed to the position of the sun with respect to the earth at different months of the year. The equinoctial maximum is observed in external current intensity which occurred mostly during the March Equinox.

Variation of Dynamical Parameters with Upper Tropospheric Potential Vorticity in Tropical Cyclone over the North Indian Ocean Using WRF Model

Meteorologists are experiencing many challenges in the reliable forecasting of the track and intensity of tropical cyclones(TC).Uses of the potential vorticity(PV)technique will enrich the current forecasting system.The use of PV analysis of TC intensification over the North Indian Ocean(NIO)is rare.In this study,the authors analyze the behaviour of upper-level PV with dynamic parameters of TCs over NIO.The authors used NCEP FNL reanalysis 1×1 degree data as input in WRF model version 4.0.3 with one-way nesting between the parent and child domains.The authors used a coupling of the Kain-Fritsch(new Eta)scheme and the WSM 6-class graupel scheme as cumulus and microphysics options to run the model.The authors found that at least one potential vorticity unit(PVU)(1 PVU=10^(-6) m^(2)s^(-1)KKg^(-1))upper PV is required to maintain the intensification of TC.Larger upper PV accelerates the fall of central pressure.The high value of upper PV yields the intensification of TC.The wind shear and upper PV exhibited almost identical temporal evolution.Upper PV cannot intensify the TCs at negative wind shear and shear above the threshold value of 12 ms^(-1).The upper PV and geopotential heights of 500 hPa change mutually in opposite trends.The upper PV calculated by the model is comparable to that of ECMWF results.Therefore,the findings of this study are admissible.

Rainfall and Temperature Variations in a Dry Tropical Environment of Nigeria

This study examines long-term rainfall and temperature variations over a dry tropical environment in Nigeria.An assessment of the variations of these weather variables showcases the extent of climate change limits and corresponding effects on the biotic environment.Rainfall and temperature data were obtained from Nigerian Meteorological Agency for a period of 31 years(1991-2020)for Kano and Katsina States.Descriptive statistics were used to determine the degree of variability of the weather variables across spatial domains.Results showed that there is a sharp contrast in mean annual rainfall amounts of 1154.1 mm and 569.6 mm for Kano and Katsina located in the dry continental and semi-arid climate zones of Nigeria respectively.It is revealed that the month of August had the highest mean monthly rainfall for both areas i.e.359 mm and 194 mm with little or no trace during the dry season.The sharp difference in rainfall amount across spatial domains of the near similar climate zones shows that the Inter-tropical Discontinuity(ITD)does not completely overwhelm the northern band of Nigeria in August.The least variable monthly rainfall was in August and July with coefficient variations(CV)of 40%and 47%for Kano and Katsina.The months of February and March had the highest CV of 557%and 273%for the respective areas.In the examined areas the wet and dry seasons are from June-September and October-May respectively.The index of rainfall variability and drought intensity for the areas ranged from 0.85-0.95 and 45%indicating moderate variability and drought respectively.Mean annual temperature values are 33.4℃and 33.8℃for Kano and Katsina.The study recommends a proper climate observing scheme,most especially for agrarian practices so as to ensure profitable outputs for human sustainability.

Relationship and Variability of Atmospheric Precipitation Characteristics in the North-West of Ukraine

The paper deals with the issues of differentiation of atmospheric precipitation into gradations according to their characteristics and established meteorological practices.The division of atmospheric precipitation into gradations allows one to have an idea of the possible consequences of their fallout on life in the area.The dependence of the average intensity of precipitation on their duration for the entire series of observations is not described by a power-law dependence with a sufficient degree of reliability,and when differentiating into gradations according to the amount of precipitation(<2.5 mm,2.5-10 mm,≥10 mm),the dependences are obtained with a high degree of correlation.The scatter of points can be explained by the presence of intermediate categories of precipitation,which does not take into account the accepted division of the data.Thus,for large values of the amount of precipitation,the existence of a sepa­rate curve is possible,since the existing classifications of precipitation imply the division of heavy showers into sepa­rate gradations.Differentiation of rains by their duration shows a stronger stratification of the field of points for shorter rains(up to 60 minutes).This stratification of the field of points is successfully differentiated into shorter segments of 20,30 minutes.Associated with the greater heterogeneity of shorter precipitation,it can be both rains of low intensi­ty and heavy downpours of short duration.The probability of the position of the maximum intensity of precipitation during rain has more significant differences for precipitation less than 2.5 mm(the curves are more curved).For rains with a precipitation amount of 2.5 mm or more,the probability curves approach straight lines,which is associated with greater heterogeneity of precipitation less than 2.5 mm.