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Assessment of the Off-season Rainfall of January to February 2020 and Its Socio Economic Implications in Tanzania: A Case Study of the Northern Coast of Tanzania

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Journal of Atmospheric Science Research 2021年第2期4卷 51-69页

作者： Kombo hamad Kai Sarah E Osima Agnes Laurence Kijazi Mohammed Khamis Ngwali asya omar hamad Tanzania Meteorological Authority(TMA) Zanzibar P.O.Box 340 ZanzibarTanzania TMA Dar es Salaam office P.O.Box 3056 Ubungo PlazaTanzania

This article examines the off season rainfall in northern coast Tanzania(NCT)including Zanzibar which occurred in January and February 2020(JF).Like the JF rainfalls of 2001,2004,2010,2016 and 2018,the JF(2020)rainfall was more unique in damages including loss of lives,properties and *** study used the NCEP/NCAR reanalysis data to examine the cause of uniqueness of JF rainfall in 2001,2004,2010,2016,2018 and 2020 over NCT and *** datasets include monthly mean u,v wind at 850,700,500,and 200 mb;SSTs,mean sea level pressure(MSLP)anomalies,Dipole Mode Index(DMI),and monthly rainfall from NCT and Zanzibar *** were processed and calculated into long term,seasonal,and monthly averages,indeed,Precipitation Index(PI)was *** analysis between the rainfall(December to January),SST,DMI and 850 mb wind vectors;and long-term percentage contribution of investigated parameters was *** revealed significant positive and negative correlations between JF rainfall,SSTs and ***,JFs of 2004 and 2016 had higher rainfalls of 443 mm with percentage contribution of up to 406%,while January and February,2020 had the highest of 269.1 and 101.1mm in Zanzibar and 295 and 146.1 mm over and NCT areas,with highest January long-term rainfall contribution of 356%in Zanzibar and 526%over *** DJF(2019/20)had the highest rainfall record of 649.5 mm in Zanzibar contributing up to 286%,while JF 2000 rainfall had a good spatial and temporal distribution over most NCT ***,2020 rainfall had impacts of more than 20 people died in Lindi and several infrastructures including Kiyegeya Bridge in Morogoro were ***,more research works on understanding the dynamics of wet and dry JF seasons should be conducted.

关键词： Indian ocean dipole Dipole mode index(DMI) Sea surface temperatures(SSTs) Rainfall Relative humidity Correlations

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Spatio-Temporal Assessment of the Performance of March to May 2020 Long Rains and Its Socio-Economic Implications in Northern Coast of Tanzania

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Atmospheric and Climate Sciences 2021年第4期11卷 767-796页

作者： Kombo hamad Kai Agnes Laurence Kijazi Sarah E. Osima Habiba Ismail Mtongori Makame omar Makame Hafidh Juma Bakari omar asya hamad Tanzania Meteorological Agency (TMA) Institute of Marine Sciences (IMS) University of Dar es Salam (UDSM) Zanzibar Tanzania Tanzania Meteorological Authority (TMA) Headquarters Ubungo Plaza Dar es Salaam Tanzania

The spatio-temporal analysis of the performance of the March to May (MAM) 2020 rainfall and its societal implications to Northern Coastal Tanzania (NCT) including Zanzibar was investigated. The uniqueness of the October to December, 2019 (OND) rainfall and the extension of the January to February, 2020 rainfall in Zanzibar which coincided with MAM 2020 rainfall was among the issues which prolonged MAM 2020 rainfall in NCT and Zanzibar. The National Center for Environmental Prediction (NCEP) in collaboration with National Center for Atmospheric Research (NCAR). Reanalysis 1 datasets of u (zonal) and v (meridional) winds, sea surface temperatures anomalies, relative humidity, amount of precipitable water and ocean net flux were analyzed. Other datasets include the Tanzania Meteorological Authority (TMA) observed rainfall records, maximum and minimum temperatures. Moreover, TMA and Intergovernmental Climate Prediction and Analysis Center (ICPAC). MAM 2020 rainfall and temperature forecast reports were interpreted. Gridded and observed datasets were calcu

关键词： March to May 2020 Rainfall Assessment Sea Surface Temperatures Anomalies (SSTA) Assessments Precipitable Water (PRW) and Ocean Net Flux Relative Humidity

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Seasonal Prediction of Tropical Cyclones and Storms over the Southwestern Indian Ocean Region Using the Generalized Linear Models

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Atmospheric and Climate Sciences 2023年第2期13卷 103-137页

作者： Kombo hamad Kai Yohanna Wilson Shaghude Christian Bs Uiso Agnes Laurent Kijazi Sarah Osima Sara Abdalla Khamis asya omar hamad Tanzania Meteorological Authority (TMA) and Institute of Marine Sciences (IMS) University of Dar es Salaam (UDSM) Zan-zibar Tanzania Department of Physics University of Dar es Salaam (UDSM) TMA Zanzibar Tanzania Department of Natural Sciences State University of Zanzibar Zanzibar Tanzania

Tropical cyclones (TCs) and storms (TSs) are among the devastating events in the world and southwestern Indian Ocean (SWIO) in particular. The seasonal forecasting TCs and TSs for December to March (DJFM) and November to May (NM) over SWIO were conducted. Dynamic parameters including vertical wind shear, mean zonal steering wind and vorticity at 850 mb were derived from NOAA (NCEP-NCAR) reanalysis 1 wind fields. Thermodynamic parameters including monthly and daily mean Sea Surface Temperature (SST), Outgoing Longwave Radiation (OLR) and equatorial Standard Oscillation Index (SOI) were used. Three types of Poison regression models (i.e. dynamic, thermodynamic and combined models) were developed and validated using the Leave One Out Cross Validation (LOOCV). Moreover, 2 × 2 square matrix contingency tables for model verification were used. The results revealed that, the observed and cross validated DJFM and NM TCs and TSs strongly correlated with each other (p ≤ 0.02) for all model types, with correlations (r) ranging from 0.62 - 0.86 for TCs and 0.52 - 0.87 for TSs, indicating great association between these variables. Assessment of the model skill for all model types of DJFM and NM TCs and TSs frequency revealed high skill scores ranging from 38% - 70% for TCs and 26% - 72% for TSs frequency, respectively. Moreover, results indicated that the dynamic and combined models had higher skill scores than the thermodynamic models. The DJFM and NM selected predictors explained the TCs and TSs variability by the range of 0.45 - 0.65 and 0.37 - 0.66, respectively. However, verification analysis revealed that all models were adequate for predicting the seasonal TCs and TSs, with high bias values ranging from 0.85 - 0.94. Conclusively, the study calls for more studies in TCs and TSs frequency and strengths for enhancing the performance of the March to May (MAM) and December to October (OND) seasonal rainfalls in the East African (EA) and Tanzania in particular.

关键词： Tropical Cyclones and Storms Frequency Thermodynamic and Dynamic Models Skill Scores TCs/TSs Variability and Verification Leave One out Cross Validation

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The Influence of Climate Change and Variability on Spatio-Temporal Rainfall and Temperature Distribution in Zanzibar

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Atmospheric and Climate Sciences 2023年第2期13卷 282-313页

作者： Abdalla Hassan Abdalla Kombo hamad Kai Sara Abdalla Khamis Afredy Lawrence Kondowe Sarah E. Osima Philemon Henry King’uza asya omar hamad Tanzania Meteorological Authority (TMA) Zanzibar Tanzania Faculty of Science State University of Zanzibar (SUZA) Zanzibar Tanzania

Climate change has resulted in serious social-economic ramifications and extremely catastrophic weather events in the world, Tanzania and Zanzibar in particular, with adaptation being the only option to reduce impacts. The study focuses on the influence of climate change and variability on spatio-temporal rainfall and temperature variability and distribution in Zanzibar. The station observation datasets of rainfall, Tmax and Tmin acquired from Tanzania Meteorological Authority (TMA) and the Coordinated Regional Climate Downscaling Experiment program (CORDEX) projected datasets from the Regional climate model HIRHAM5 under driving model ICHEC-EC-EARH, for the three periods of 1991-2020 used as baseline (HS), 2021-2050 as near future (NF) and 2051-2080 far future (FF), under two representative concentration pathways (RCP) of 4.5 and 8.5, were used. The long-term observed Tmax and Tmin were used to produce time series for observing the nature and trends, while the observed rainfall data was used for understanding wet and dry periods, trends and slope (at p ≤ 0.05) using the Standardized Precipitation Index (SPI) and the Mann Kendall test (MK). Moreover, the Quantum Geographic Information System (QGIS) under the Inverse Distance Weighting (IDW) interpolation techniques were used for mapping the three decades of 1991-2000 (hereafter D1), 2001-2010 (hereafter D2) and 2011-2020 (hereafter D3) to analyze periodical spatial rainfall distribution in Zanzibar. As for the projected datasets the Climate Data Operator Commands (CDO), python scripts and Grid analysis and Display System (GrADS) soft-wares were used to process and display the results of the projected datasets of rainfall, Tmax and Tmin for the HS, NF and FF, respectively. The results show that the observed Tmax increased by the rates of 0.035℃ yr-1 and 0.0169℃ yr-1, while the Tmin was i

关键词： Climate Change Climate Variability Spatial and Temporal Distribution Temperature Rainfall CORDEX

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The Influence of Climate Variability on the Watermelon Production in Zanzibar

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Atmospheric and Climate Sciences 2023年第1期13卷 44-61页

作者： asya omar hamad Kombo hamad Kai Agnes Kijazi Sara Abdalla Khamis Abdalla Hassan Abdalla Hassan Khatib Ame Masoud Makame Faki Faki Ali Ali Tanzania Meteorological Authority (TMA) Zanzibar Office Zanzibar Tanzania TMA Dar es Salaam Office Dar es Salaam Tanzania The State University of Zanzibar (SUZA) Zanzibar Tanzania

Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Currently, there is either no or scant information that describes the influence of climate changes and variability to watermelon production in Zanzibar. Thus, this study aimed to determine the influence of climate variability on the quantity of watermelon production in Zanzibar. The study used both primary and secondary datasets, which include the anecdotal information collected from interviewers’ responses from four districts of Unguja and Pemba, and climate parameters (rainfall, maximum and minimum temperature (Tmax and Tmin) acquired from Tanzania Meteorological Authority (TMA) at Zanzibar offices. Pearson correlation was used for analyzing the association between watermelon production and climate parameters, while paired t-test was applied to show the significance of the mean differences of watermelon and climate parameters for two periods of 2014-2017 and 2018-2021, respectively. Percentage changes were used to feature the extent to which the two investigated parameters affect each other. The anecdotal responses were sorted, calculated in monthly and seasonal averages, plotted and then analyzed. Results have shown a strong correlation (r = 0.8 at p ≤ 0.02, and r = 0.7) between watermelon production, Tmax and rainfall during OND, especially in Unguja, as well as Tmin during JJA (i.e. r = - 0.8 at p ≤ 0.02) in Pemba. Besides, results have shown the existence of significant differences between the means of watermelon production and climate parameter for the two stated periods, indicating that the climate parameters highly affects the watermelon production by either enhancing or declining the yields by 69% - 162% and 17% - 77%, respectively. Moreover, results have shown that respondents were aware that excess temperature intensity during dry periods can le

关键词： Watermelon March to May (MAM) and October to November (OND) Seasonal Rainfall Maximum and Minimum Temperature Anecdotal Information

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Improving the Segmentation of Arabic Handwriting Using Ligature Detection Technique

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Computers, Materials & Continua 2024年第5期79卷 2015-2034页

作者： Husam Ahmad Al hamad Mohammad Shehab College of Computer Sciences and Informatics Amman Arab UniversityAmman11953Jordan

Recognizing handwritten characters remains a critical and formidable challenge within the realm of computervision. Although considerable strides have been made in enhancing English handwritten character recognitionthrough various techniques, deciphering Arabic handwritten characters is particularly intricate. This complexityarises from the diverse array of writing styles among individuals, coupled with the various shapes that a singlecharacter can take when positioned differently within document images, rendering the task more perplexing. Inthis study, a novel segmentation method for Arabic handwritten scripts is suggested. This work aims to locatethe local minima of the vertical and diagonal word image densities to precisely identify the segmentation pointsbetween the cursive letters. The proposed method starts with pre-processing the word image without affectingits main features, then calculates the directions pixel density of the word image by scanning it vertically and fromangles 30° to 90° to count the pixel density fromall directions and address the problem of overlapping letters, whichis a commonly attitude in writing Arabic texts by many people. Local minima and thresholds are also determinedto identify the ideal segmentation area. The proposed technique is tested on samples obtained fromtwo datasets: Aself-curated image dataset and the IFN/ENIT dataset. The results demonstrate that the proposed method achievesa significant improvement in the proportions of cursive segmentation of 92.96% on our dataset, as well as 89.37%on the IFN/ENIT dataset.

关键词： Arabic handwritten segmentation image processing ligature detection technique intelligent recognition

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Spatio-Temporal Assessment of the Performance of March to May 2020 Long Rains and Its Socio-Economic Implications in Northern Coast of Tanzania

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Atmospheric and Climate Sciences（大气和气候科学） 2021年第4期

作者： Kombo hamad Kai Agnes Laurence Kijazi Sarah E. Osima Habiba Ismail Mtongori Makame omar Makame Hafidh Juma Bakari omar asya hamad

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Predictive modeling of critical temperatures in magnesium compounds using transfer learning

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Journal of Magnesium and Alloys 2024年第4期12卷 1540-1553页

作者： Surjeet Kumar Russlan Jaafreh Subhajit Dutta Jung Hyeon Yoo Santiago Pereznieto Kotiba hamad Dae Ho Yoon School of Advanced Materials Science&Engineering Sungkyunkwan University Suwon 16419Republic of Korea

This study presents a transfer learning approach for discovering potential Mg-based superconductors utilizing a comprehensive target ***,a large source dataset(Bandgap dataset)comprising approximately∼75k compounds is utilized for pretraining,followed by fine-tuning with a smaller Critical Temperature(T_(c))dataset containing∼300 ***,there is a significant improvement in the performance of the transfer learning model over the traditional deep learning(DL)model in predicting ***,the transfer learning model is applied to predict the properties of approximately 150k *** are validated computationally using density functional theory(DFT)calculations based on lattice dynamics-related ***,to demonstrate the extended predictive capability of the transfer learning model for new materials,a pool of virtual compounds derived from prototype crystal structures from the Materials Project(MP)database is generated.T_(c) predictions are obtained for∼3600 virtual compounds,which underwent screening for electroneutrality and thermodynamic *** Extra Trees-based model is trained to utilize E_(hull)values to obtain thermodynamically stable materials,employing a dataset containing Ehull values for approximately 150k materials for *** with Ehull values exceeding 5 meV/atom were filtered out,resulting in a refined list of potential Mg-based *** study showcases the effectiveness of transfer learning in predicting superconducting properties and highlights its potential for accelerating the discovery of Mg-based materials in the field of superconductivity.

关键词： Superconductivity Critical temperature Transfer learning Crystal structure features Thermodynamic stability

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Seasonal Prediction of Tropical Cyclones and Storms over the Southwestern Indian Ocean Region Using the Generalized Linear Models

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Atmospheric and Climate Sciences（大气和气候科学） 2023年第2期

作者： Kombo hamad Kai Yohanna Wilson Shaghude Christian Bs Uiso Agnes Laurent Kijazi Sarah Osima Sara Abdalla Khamis asya omar hamad

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Flexible pavement longitudinal joint quality evaluation using non-destructive testing

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Journal of Road Engineering 2024年第2期4卷 189-202页

作者： hamad Bin Muslim Syed Waqar Haider Lev Khazanovich Department of Civil and Environmental Engineering Michigan State UniversityEast LansingMI 48824USA Department of Civil and Environmental Engineering University of PittsburghPittsburghPA 15261USA

Longitudinal joint construction quality is critical to the life of flexible *** deteriorated longitudinal joints has become a challenge for many highway *** the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less *** quality control(QC)and quality assurance(QA)plans provide limited ***,the risk of missing areas with poor joint compaction is significant.A density profiling system(DPS)is a non-destructive alternative to conventional destructive evaluation *** can provide quick and continuous real-time coverage of the compaction during construction in *** paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction *** paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal *** paper proposes a dielectric-based longitudinal joint quality index(LJQI)to evaluate the relative compaction of the joint during *** also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints,identify locations of poor quality during construction,and achieve better-performing flexible pavements.

关键词： Sustainable pavements Dielectric/density profiling system Quality assurance Non-destructive testing Asphalt longitudinal joint

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