Urban Heat Islands and Vegetation Cover as a Controlling Factor

Cities play an important role in climate change mitigation and adaptation and enhancingclimate resilience of their slum and vulnerable residents. Climate change adds to existingchallenges faced by cities. Climate change, together with a decrease in absorption capacity ofgreenhouse gasses due reduction in the amount of green cover, parks, trees and agriculturalsurfaces in urban areas, poses serious threats to urban infrastructure, access to basic servicesand quality of life in cities and negatively affect the urban economy. At the same time, rapidurban growth, growing urban poverty and increasing food prices raise concerns about urbanfood security, especially for the poor. Cities are highly vulnerable to disruption in critical(food) supplies and climate change exacerbates this vulnerability.The main objective of this study is to examine the spatial pattern of surface temperature in theKesbewa Urban Council Area and temperature variation with the different UPAF (UrbanPeri-urban and Agriculture and Forestry) regions using space born techniques and groundverifications.GIS and Remote Sensing techniques were the main analytical tools of this study in datacollection as well as data processing and analysis. Landsat ETM+ image from 2003 used toextract the surface temperature layer and model has verified using air temperature datacollected throughout the KUC area for the last five months period using 22 HOBO metersinstalled in different UPAF regions in the city. UPAF regions have identified and demarcatedusing Google image and visually interpreted with the field experiences.The surface temperature model developed using satellite images is positively correlated withthe ground temperature data collected and results revealed that there is a very positiverelationship between the UPAF regions and the surface temperature.

Model for River Bank Conservation and Proper Land Use Planning

This study describes a case study involving the use of bioengineering and rock structures torestore an eroded bank of the Deduru Oya, and restoration of ecological amenities thatexisted prior to disturbances by man and a major flood event, sustainable plot level landimprovement by agro forestry farming techniques. In addition, this study exposed thatimproper land use activities and illegal activities done by the people directly influence to thenatural process of Daduru Oya river basin. Thus, the study emphasized that banning riversand mining in the Deduru Oya until improvements of the sand deposits again at the river bedthere is no balance between the deposition and transportation, and until the river has adequatecompletion of sand in the banks and the river bed. If not that will be creates lots ofenvironmental problems in the area.Therefore, considering the river bank conservation by bio engineering best practice of landuse in the Deduru Oya lower basin were helpful to protect river bank erosion, groundwaterconservation, riparian buffer zone redevelopment and water and land management. Bothliving and nonliving plants can be used. Nonliving plants are used as construction materials,similar to engineered materials. Planted vegetation controls erosion and serves as goodwildlife and fisheries habitat in riparian systems. Guidelines are generally lacking for use ofbioengineering treatment on stream banks, which often explains why bioengineering is notused more often. The management strategy which is used (Bio engineering technology forconserve the river banks) are help to control soil erosion by runoff water of the river buffer,reduce silting in river bed by eroded soil and other materials, Increase the water qualitypurifying water by the roots of plants, increase green canopies and green belt beside of theriver, control the flood damage, bio-diversity conservation. This is socially acceptable,economically and environmentally sustainable technology. If this technology can be appliedfor the other river banks development, that will help to protect rivers and associatedenvironment. It is not applicable this technology for the entire river banks in Sri Lanka butshould have to identify the suitable place and do the implementation. This is low cost, ecofriendlyend sustainable technology. Introducing endemic species (Mee -Madhuca longifolia,Midella - Barringtonia aceamosa, Kumbuk - Peminalia arguna, Rambuk -Erianthusarundinaceus, Bamboo Three Types) to the river bank is extensively helpful to conservebiological diversity and have medicinal and cultural values. Moreover, agroforestry farminggain much help to maintain keep healthy of the soil fertility sustainably

Student Satisfaction with Online Learning during the COVID-19 Pandemic: A Study at State Universities in Sri Lanka

This quantitative study investigated the determinants of students’ satisfaction with their online learning experience at Sri Lankan universities during the COVID-19 pandemic. The data was collected from 1376 undergraduates enrolled in various courses in humanities and social sciences at three state-owned universities in the country. The results of the Structural Equation Modeling (SEM) revealed that the independent variables of the model, namely perceived learner motivation, perceived challenges of e-learning, and interaction significantly affected students’ satisfaction with their new online learning experience. Out of the three variables, learner motivation exerted the strongest effect on students’ satisfaction, implying the crucial role self-regulated learning—characterized by motivation—plays in online learning environments. The study has several implications for both creating and ensuring the long-term sustainability of productive and student-friendly online learning spaces in higher education

A Validation of Observed Meteotsunami in the West Coast of Sri Lanka with European Centre of Medium Range Weather Forecasts (ECMWF) Modelled Data

Metetsunamis are local regional events originating from perturbation of water levels by the impulse of particularly pressure drop in a disturbed atmospheric weather system and amplified to a destructive Tsunami wave with the combined effect of resonance. For the preliminary investigation a Meteotsunami event was analysed for one minute’s frequency data collected in situ sea level measuring station established in Colombo, Sri Lanka under the authority of National Aquatic Resources Research and Development Agency (NARA) with the supervision of Intergovernmental Oceanographic Commission (IOC). The contribution of disturbed weather system was analysed using wind speed (ms-1), atmospheric pressure (hPa) 10 min frequent reading from the Meteorological Department of Sri Lanka and weather station established under the bilateral project of University of Notre dame and NARA. The observed Meteotsunami event was validated using gridded modelled data (12.5 km resolution) obtained from the European Centre of Medium Range Weather Forecasts (ECMWF) and analysed using 6 hourly frequent atmospheric pressure (hPa) data, U and V at wind data at 10 m height and significant wave height. For the identification of Meteotsunami events, observed tide gauge readings were analysed in few different steps. The tidal constituents were quantified using harmonic analysis to obtained astronomical effect removed sea level variation and filtered to isolate Meteotsunami events using math lab software.According to the in situ observation data the atmospheric pressure gradient was recorded as 1008-1001 milibar hours while the modelled value dropped from 1009 to 1002 milibar hours. The observed wind speed was increased from 14.21 to 31.90 mph within 4 hours of time period and ECMWF wind speed increased from 11.02 to 19.94 mph with positive deviation. The observed wave height of Metiotsunami event was >0.3 m while model derived wave height was 0.6 m during the low tide period of the day. According to the threshold criterion suggested by Monserrat for classifying Meteotsunami, resulted wave amplitude of observation data exceeded 4 x σ, where σ is standard deviation of astronomical effect removed residual sea level time series. Further studies are required for the investigation of propagation mechanism with amplifying through the bays with the resonance effects. Further high frequency data are insufficient for the investigation of correlation with synoptic scale meteorological event.The ECMWF model is highly recommended for the prediction of disturbed atmospheric system and related ocean based extreme event forecast for prevention of ocean, atmospheric hazards and mitigation of vulnerability with the effect of global change giving real value of lives in the earth.Keywords: Sea level, Meteotsunami, Tsunami, Atmospheric, Resonanc

Satellite-based meteorological and agricultural drought monitoring for agricultural sustainability in Sri Lanka

For Sri Lanka, as an agricultural country, a methodical drought monitoring mechanism, including spatial and temporal variations, may significantly contribute to its agricultural sustainability. Investigating long-term meteorological and agricultural drought occurrences in Sri Lanka and assessing drought hazard at the district level are the main objectives of the study. Standardized Precipitation Index (SPI), Rainfall Anomaly Index (RAI), and Vegetation Health Index (VHI) were used as drought indicators to investigate the spatial and temporal distribution of agriculture and meteorological droughts. Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) data from 1989 to 2019 was used to calculate SPI and RAI. MOD13A1 and MOD11A2 data from Moderate Resolution Imaging Spectroradiometer (MODIS) from 2001 to 2019, were used to generate the Vegetation Condition Index (VCI) and Temperature Condition Index (TCI). Agricultural drought monitoring was done using VHI and generated using the spatial integration of VCI and TCI. Thus, various spatial data analysis techniques were extensively employed for vector and raster data integration and analysis. A methodology has been developed for the drought declaration of the country using the VHI-derived drought area percentage. Accordingly, for a particular year, if the country-wide annual extreme and severe drought area percentage based on VHI drought classes is =30%, it can be declared as a drought year. Moreover, administrative districts of Sri Lanka were classified into four hazard classes, No drought, Low drought, Moderate drought, and High drought, using the natural-beak classification scheme for both agricultural and meteorological droughts. The findings of this study can be used effectively by the relevant decision-makers for drought risk management (DRM), resilience, sustainable agriculture, and policymaking

Spatiotemporal variability of lightning activity over the railway network in Sri Lanka with special attention to the proposed suburban railway electrification network

This study is oriented towards the investigation of the spatiotemporal variability of the lightning activity over the railway network in Sri Lanka using -lightning data from 1998 to 2014 that were downloaded from the database of Lightning Imaging Sensor (LIS) onboard NASA’s Tropical Rainfall Measuring Mission (TRMM). The study has also been extended to study the lightning activity over the proposed suburban railway electrification network. GIS was used to conduct an annual and seasonal analysis of the railway network, which consists of nine major railway lines, to identify vulnerable stations and segments. The average annual lightning flash density over a 1447 km-long railway network of Sri Lanka varies between 5.08–16.58 flashes/(km2 year). The railway lines run across the western and southern regions of the country have been identified as being in areas with higher lightning activity. In comparison to other railway lines, the Kelani Valley line in the Colombo district and Colombo-Maradana to Polgahawela segment of the Mainline are particularly vulnerable to lightning activity. These areas have also been recognized as regions with higher population density. The proposed 102 km long railway electrification network in Sri Lanka is also within higher population density segments, with higher lightning flash density values between 10.55–16.53 flashes/(km2 ·year). As a result, to improve the operational efficiency of the proposed electrification network, a fully coordinated lightning protection system in accordance with the findings of this study is strongly suggested

A Functional Analysis of Pedotransfer Functions Developed for Sri Lankan soils: Applicability for Process-Based Crop Models

As measurements are expensive and laborious, the estimation of soil hydraulic properties using pedotransfer functions (PTFs) has become popular worldwide. However, the estimation of soil hydraulic properties is not the final aim but an essential input value for other calculations and simulations, mostly in environmental and crop models. This modeling approach is a popular way to assess agricultural and environmental processes. However, it is rarely used in Sri Lanka because soil hydraulic data are rare. We evaluated the functionality of PTFs (developed to estimate field capacity (FC) and the permanent wilting point (PWP) of Sri Lankan soils) for process-based crop models. We used the Agricultural Production Systems sIMulator (APSIM) as the test model. Initially, we confirmed the importance of PWP (LL15) and FC (DUL) by assessing the sensitivity of the soil input parameters on the growth and yield of rice under rainfed conditions. We simulated the growth and yield of rice and the four selected outputs related to the APSIM soil module using the measured and estimated values of FC and PWP. These simulations were conducted for ten years in 16 locations of Sri Lanka, representing wet, intermediate, and dry zones. The simulated total aboveground dry matter and weight of the rough rice, using both input conditions (the measured and PTF-estimated soil hydraulic properties), showed good agreement, with no significant differences between each other. Outputs related to the soil module also showed good agreement, as no significant differences were found between the two input conditions (measured and PTF-estimated soil hydraulic properties). Although the DUL and LL15 are the most influential parameters for the selected outputs of APSIM–Oryza, the estimated FC and PWP values did not change the predictive ability of APSIM. In this way, the functionality of PTFs for APSIM crop modeling is confirmed

Rainfall variability and trends over the African continent using TAMSAT data (1983-2020): towards climate change resilience and adaptation

This study reveals rainfall variability and trends in the African continent using TAMSAT data from 1983 to 2020. In the study, a Mann–Kendall (MK) test and Sen’s slope estimator were used to analyze rainfall trends and their magnitude, respectively, under monthly, seasonal, and annual timeframes as an indication of climate change using different natural and geographical contexts (i.e., sub-regions, climate zones, major river basins, and countries). The study finds that the highest annual rainfall trends were recorded in Rwanda (11.97 mm/year), the Gulf of Guinea (river basin 8.71 mm/year), the tropical rainforest climate zone (8.21 mm/year), and the Central African region (6.84 mm/year), while Mozambique (-0.437 mm/year), the subtropical northern desert (0.80 mm/year), the west coast river basin of South Africa (-0.360 mm/year), and the Northern Africa region (1.07 mm/year) show the lowest annual rainfall trends. There is a statistically significant increase in the rainfall in the countries of Africa’s northern and central regions, while there is no statistically significant change in the countries of the southern and eastern regions. In terms of climate zones, in the tropical northern desert climates, tropical northern peninsulas, and tropical grasslands, there is a significant increase in rainfall over the entire timeframe of the month, season, and year. This implies that increased rainfall will have a positive effect on the food security of the countries in those climatic zones. Since a large percentage of Africa’s agriculture is based only on rainfall (i.e., rain-fed agriculture), increasing trends in rainfall can assist climate resilience and adaptation, while declining rainfall trends can badly affect it. This information can be crucial for decision-makers concerned with effective crop planning and water resource management. The rainfall variability and trend analysis of this study provide important information to decision-makers that need to effectively mitigate drought and flood risk

Determination of the Potential of Meteotsunami in the West Coast of Sri Lanka

Meteotsunami are tsunami-like waves of meteorological origin than of seismic origin. This study is done as the first determination of Meteotsunami around the Sri Lankan coast. Sea level data were used from permanent tide gauge stations establish Colombo, Trincomalee, Kirinda interconnected to the global sea level monitoring network establish by the inter-governmental oceanographicnbspnbsp commission. Using high frequency readings, specific events were identified and further analyzed to remove tidal constituents and to obtain residual sea level variations. Residual sea level height was fast filtered and high frequency detected to identify Tsunami waves as same as seismic tsunami waves. The atmospheric pressure gradient was 1008-1011milibar hours while the wind speed increase from 14.21 to 31.90 mph in during same period. The amplitudenbspnbsp of isolated meteotsunami event was higher than four time of residualrsquos STD (sigma). Meteotsunami event was identified during low tide with wave height gt 0.3 m

Determination of the Potential of Meteotsunami in the West Coast of Sri Lanka

Meteotsunami are tsunami-like waves of meteorological origin than of seismic origin. This study is done as the first determination of Meteotsunami around the Sri Lankan coast. Sea level data were used from permanent tide gauge stations establish Colombo, Trincomalee, Kirinda interconnected to the global sea level monitoring network establish by the inter-governmental oceanographicnbspnbsp commission. Using high frequency readings, specific events were identified and further analyzed to remove tidal constituents and to obtain residual sea level variations. Residual sea level height was fast filtered and high frequency detected to identify Tsunami waves as same as seismic tsunami waves. The atmospheric pressure gradient was 1008-1011milibar hours while the wind speed increase from 14.21 to 31.90 mph in during same period. The amplitudenbspnbsp of isolated meteotsunami event was higher than four time of residualrsquos STD (sigma). Meteotsunami event was identified during low tide with wave height gt 0.3 m