Spatial Distribution Of Drought Research Articles

Dynamic Evolution and Copula-Based Multivariable Frequency Analysis of Meteorological Drought Considering the Spatiotemporal Variability in Northwestern China

Meteorological drought is a continuous spatiotemporal phenomenon that poses a serious threat to water resource security. Dynamic evolution and multivariable frequency analysis of meteorological drought are important for effective drought mitigation and risk management. Therefore, this study aims to analyze meteorological drought events in northwestern China between 1960 and 2018 based on the standardized precipitation evapotranspiration index (SPEI) through a three-dimensional identification method. This study investigates the meteorological drought dynamic evolution on different time and space scales and evaluates the frequency analysis considering the spatiotemporal variability based on Copula. The results show that SPEI presents an upward trend in Northwestern China. A trend towards increased humidity is observed in arid regions, contrasted by a trend towards aridification in semi-arid and semi-humid areas, indicating that the spatial distribution of drought in the study area tends towards homogenization. The possibility of high-intensity drought events occurring in the same area was relatively low, whereas low-intensity drought events were frequent. Additionally, this study analyzes the dynamic migration process of individual drought events from a three-dimensional perspective. Neglecting any one drought variable could significantly underestimate the occurring probability of severe drought events. Therefore, a multivariable frequency analysis considering the spatiotemporal variability plays a crucial role in the formulation of drought prevention and mitigation strategies, as well as drought forecasting.

Remote-Sensing Drought Monitoring in Sichuan Province from 2001 to 2020 Based on MODIS Data

In this study, four drought monitoring indices were selected to simulate drought monitoring in the study area and a correlation analysis was conducted using the self-calibrated Palmer Drought Index (sc-PDSI) to screen for the most suitable drought monitoring index for the study area. Then, the spatio-temporal variation characteristics of drought in the study area were discussed and analyzed. The results showed that the Crop Water Stress Index (CWSI) was most suitable for drought monitoring in the Sichuan Province. CWSI had the best monitoring in grasslands (r = 0.48), the worst monitoring in woodlands (r = 0.43) and the highest fitting degree of overall correlation (r = 0.47). The variation of drought time in the Sichuan Province showed an overall trend of wetting and the drought situation was greatly alleviated. In the past 20 years, the dry years in the Sichuan Province were from 2001 to 2007, in which the driest years were 2006 and 2007; 2012–2013 was the transition interval between drought and wet; any year from 2013 to 2020 was a wet year, showing a transition trend of “drought first and then wet”. The spatial distribution of drought was greater in the south than in the north and greater in the west than in the east. Panzhihua City and the southern part of the Liangshan Prefecture were the most arid areas, while the non-arid areas were the border zone between the western Sichuan Plateau and the Sichuan Basin. Looking at the spatial distribution of drought, “mild drought” accounted for the largest percentage of the total area (60%), mainly concentrated in the western Sichuan plateau. The second largest was “drought free” (33%), mostly concentrated in the transition area between the western Sichuan Plateau and the Sichuan Basin (western Aba Prefecture, Ya’an City, Leshan City and northern Liangshan Prefecture). The area of “moderate drought” accounted for a relatively small proportion (6%), mainly concentrated in Panzhihua City, the surrounding areas of Chengdu City and the southern area of the Liangshan Prefecture. The area of severe drought accounted for the least (1%), mostly distributed in Panzhihua City and a small part in the southern Liangshan Prefecture. The drought center ranged from 101.8° E to 103.6° E and 28.8° N to 29.8° N, with the movement trend of the drought center moving from the northeast to the southwest to the northeast.

How agricultural droughts are contributing to child undernutrition in sub-Saharan Africa

Countries in sub-Saharan Africa (SSA) have some of the highest levels of child malnutrition, with more than one third of children under five in the region characterized as chronically undernourished. High reliance on subsistence farming, poor adoption of irrigation technologies and variable climate conditions make populations in SSA highly vulnerable to malnutrition during droughts. We use anthropometric data for 570,540 children under the age of five from 34 countries in SSA in combination with high resolution agricultural and climate data to estimate the association between agricultural droughts and child undernutrition in the region. We use global gridded data on the geographical distribution of crop areas for 19 major crops. Data on crop planting and harvesting dates are also collected for each crop. The Standardized Precipitation Evapotranspiration Index (SPEI), a multi-scalar drought index, is used to measure the intensity and spatial distribution of droughts during key periods of agricultural production (planting, growth and harvesting) and of different duration (seasonal and long-lasting droughts). Our preliminary analysis shows that droughts during the main crop growing season are associated with increased risk of child undernutrition in SSA. As a next step, we will quantify the impact of droughts during the planting and harvesting seasons and for specific crops. We will additionally investigate whether droughts impact pastoral communities, for example through livestock loss. The findings presented in this study call for urgent action to improve drought monitoring and response in SSA where the risks to child health posed by global warming are considerable. Under climate change, the severity and frequency of extreme weather and climate events, including droughts, are projected to increase in the future, which will place millions of children at risk of hunger unless timely actions plans are taken to improve food security in the region. Key words: drought, undernutrition, agriculture, sub-Saharan Africa

Seasonal dynamics of agro-meteorological drought in Mberengwa and Zvishavane districts between 2017 and 2020, Zimbabwe

Drought severity is increasing in Southern Africa which is affecting rain-fed agriculture, the main source of livelihood in most countries in this region. The study assessed the seasonal spatio-temporal dynamics of agro-meteorological drought between 2017 and 2020 in Mberengwa and Zvishavane districts. An empirical research design supported by quantitative geographical information system techniques for data analysis was adopted in this study. Remote sensing data and precipitation records from the Meteorological Services Department were main data sources in this study. Microsoft excel 2013, SPI generator and ArcMap 10.5 software were used for data analysis in this study. Results showed that both Mberengwa and Zvishavane districts experienced an increasing trend in spatial coverage of drought from 2017 to 2019 before a slight decline in 2020. From 2017, drought severity increased in terms of spatial coverage with this spatial distribution increasing to almost over ¾ of the wards in both Mberengwa and Zvishavane districts between 2018 and 2020. Since 2017, on a ward level basis, both districts have been experiencing late onset and early cessation of the rain season as shown by increasingly dry October, November and March, months which determine the length of crop growing season in these two districts. Results indicated that the month of March was drier in Mberengwa whilst the month of December was drier in Zvishavane, an indication of more mid-season dry spells in Zvishavane and earlier rainfall cessation in Mberengwa. Drought is worsening in both Mberengwa and Zvishavane districts; hence, long-term drought resilience interventions are required to improve drought resilience of communities in these areas. The study recommends the Government of Zimbabwe and other stakeholders of drought resilience building like CARE International, World Vision among others to prioritise launching of resilience building initiatives in most vulnerable areas whilst guided by fine empirical information on spatial distribution of drought.

Drought and flood characteristics in the farming-pastoral ecotone of northern China based on the Standardized Precipitation Index

The farming-pastoral ecotone of northern China (FPENC) provides an important ecological barrier which restrains the invasion of desert into Northwest China. Studying drought and flood characteristics in the FPENC can provide scientific support and practical basis for the protection of the FPENC. Based on monthly precipitation data from 115 meteorological stations, we determined the changes in climate and the temporal and spatial variations of drought and flood occurrence in the FPENC during 1960–2020 using the Standardized Precipitation Index (SPI), Morlet wavelet transform, and inverse distance weighted interpolation method. Annual precipitation in the FPENC showed a slightly increasing trend from 1960 to 2020, with an increasing rate of about 1.15 mm/a. The interannual SPI exhibited obvious fluctuations, showing an overall non-significant upward trend (increasing rate of 0.02/a). Therefore, the study area showed a wetting trend in recent years. Drought and flood disasters mainly occurred on an interannual change cycle of 2–6 and 9–17 a, respectively. In the future, a tendency towards drought can be expected in the FPENC. The temporal and spatial distribution of drought and flood differed in the northwestern, northern, and northeastern segments of the FPENC, and most of the drought and flood disasters occurred in local areas. Severe and extreme drought disasters were concentrated in the northwestern and northeastern segments, and severe and extreme flood disasters were mainly in the northeastern segment. Drought was most frequent in the northwestern segment, the central part of the northeastern segment, and the northern part of the northern segment. Flood was most frequent in the western part of the northwestern segment, the eastern part of the northeastern segment, and the eastern and western parts of the northern segment. The accurate evaluation of the degrees of drought and flood disasters in the FPENC will provide scientific basis for the regional climate study and critical information on which to base decisions regarding environmental protection and socio-economic development in this region.

Assessment of spatial interpolation techniques for drought severity analysis in Salt Lake Basin

Drought risk management requires drought monitoring which is usually carried out by applying different drought indices which are, effectively, continuous functions of precipitation and other meteorological data. However, these indices are estimated at specific locations, and the spatial distribution of drought must be calculated in the form of maps. Geostatistical and deterministic techniques make it possible to interpolate spatially-referenced data. These methods are able to estimate values for arbitrary locations in regions of interest. The current study applied five spatial interpolation methods (inverse distance weighted, global polynomial interpolation, local polynomial interpolation, radial basic function, and kriging [with 4 sub-types]) to extract maps of SPI at 60 rain-gauge stations in the Salt Lake Basin of Iran. Based on the root mean square error, mean absolute error, and mean bias error values of estimations made using sampled data from 1969 to 2009, RBF and kriging techniques were the best and most suitable methods for the spatial analysis of SPI in the study area. The current study applied five spatial interpolation methods (inverse distance weighted, global polynomial interpolation, local polynomial interpolation, radial basic function, and kriging [with 4 sub-types]) to extract maps of SPI at 60 rain-gauge stations in the Salt Lake Basin of Iran. Based on the root mean square error, mean absolute error, and mean bias error values of estimations made using sampled data from 1969 to 2009, RBF and kriging techniques were the best and most suitable methods for the spatial analysis of SPI in the study area.

Analysis of the spatial distribution of the drought in the Lim valley and on the upper course of the river Ibar in Montenegro

This paper analyzed the spatial distribution of drought at meteorological stations on the Lim valley (Plav, Andrijevica, Berane and Bijelo Polje) and on the upper course of the river Ibar (Rožaje). The goal of this research is to point out the modern climatic characteristics in relation to the current state of aridization, which is a limiting factor for economy of the population in many areas throughout the world. The method used for such purposes is the De Marton drought index. Results of the research indicated a decrease in the annual drought index through the Lim valley, with the highest values for Plav (IDM=61,9), and the lowest for the lowest downstream station Bijelo Polje (IDM=41,3). The values of this climate index indicate the conditions of very humid (Berane, Bijelo Polje and Rožaje) and extremely humid climates (Plav and Andrijevica), with huge drainage and forest vegetation. By applying the De Marton index on a seasonal and monthly level, the highest values of this indicator were established in the winter season.

Spatiotemporal Characteristics of Drought and Driving Factors Based on the GRACE-Derived Total Storage Deficit Index: A Case Study in Southwest China

Drought monitoring is useful to minimize the impact of drought on human production and the natural environment. Gravity Recovery and Climate Experiment (GRACE) satellites can directly capture terrestrial water storage anomalies (TWSA) in the large basin, which represents a new source of hydrological information. In this study, the GRACE-based total storage deficit index (TSDI) is employed to investigate the temporal evolution and spatial distribution of drought in Southwest China from 2003 to 2016. The comparison results of TSDI with the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), and the self-calibrating Palmer drought severity index (SC-PDSI) show that TSDI has significant consistency with them, which verifies the reliability of TSDI. The spatial distribution of TSDI was more consistent with the governmental drought reports than SC-PDSI in the most severe drought event from September 2009 to April 2010. Finally, the links between drought and climate indicators are investigated using the partial least square regression (PLSR) model. The results show that insufficient precipitation has the most significant impact on drought in Southwest China, followed by excessive evaporation. Although Southwest China is selected as a case study in this paper, the method can be applied in other regions as well.

Investigation of spatiotemporal variation of drought in Iran during the last five decades

The present study was conducted to assess the changes in Iran's drought severity for the duration of 1964 to 2014. For this purpose, the spatial distribution of drought was annually and seasonally evaluated using climate data from 26 synoptic stations over Iranian territory based on standardized precipitation index (SPI). In this regard, the climate classification in the study area was performed applying Dermartone method. Moreover, the annual and seasonal values of SPI were calculated for the whole Iranian territory and each climate region. The SPI index for monotonic trend was calculated in each climate region utilizing Mann-Kendall and Theil Sen estimators. Our results implied that the minimum and maximum values of SPI (-3.86 and 2.89, respectively) appeared during spring in dry and Mediterranean climate regions. In addition, the maximum and minimum values of annual continuous SPI appeared in 1999-2004 and 1974-1982, respectively. The maximum and minimum values of seasonal continuous SPI also appeared for a duration of 9 years during summers respectively in the period of 1977 to 1985 and springs in the period of 2006 to 2014. The application of Mann-Kendall and Theil Sen estimator analyses revealed that 9 out of 26 stations had a significant decreasing SPI trend. Moreover, the annual and seasonal time series in moderately dry regions indicated a meaningfully decreasing trend in winter and annual SPI. Additionally, winter, spring, autumn and annual values of SPI had a meaningful decreasing trend in the Mediterranean climate region. In dry and very wet climate regions, no obvious trend was detected for the annual or seasonal SPI index.

Long-Term Spatiotemporal Variations in Soil Moisture in North East China Based on 1-km Resolution Downscaled Passive Microwave Soil Moisture Products

It is very important to analyze and monitor agricultural drought to obtain high temporal-spatial resolution soil moisture products. To overcome the deficiencies of passive microwave soil moisture products with low resolution, we construct a spatial fusion downscaling model (SFDM) using Moderate Resolution Imaging Spectroradiometer (MODIS) data. To eliminate the inconsistencies in soil depth and time among different microwave soil moisture products (Advanced Microwave Scanning Radiometer on the Earth Observing System (AMSR-E) and its successor (AMSR2) and the Soil Moisture Ocean Salinity (SMOS)), a time series reconstruction of the difference decomposition (TSRDD) method is developed to create long-term multisensor soil moisture datasets. Overall, the downscaled soil moisture (SM) products were consistent with the in situ measurements (R > 0.78) and exhibited a low root mean square error (RMSE < 0.10 m3/m3), which indicates good accuracy throughout the time series. The downscaled SM data at a 1-km spatial resolution were used to analyze the spatiotemporal patterns and monitor abnormal conditions in the soil water content across North East China (NEC) between 2002 and 2018. The results showed that droughts frequently appeared in western North East China and southwest of the Greater Khingan Range, while drought centers appeared in central North East China. Waterlogging commonly appeared in low-terrain areas, such as the Songnen Plain. Seasonal precipitation and temperature exhibited distinct interdecadal characteristics that were closely related to the occurrence of extreme climatic events. Abnormal SM levels were often accompanied by large meteorological and natural disasters (e.g., the droughts of 2008, 2015, and 2018 and the flooding events of 2003 and 2013). The spatial distribution of drought in this region during the growing season shows that the drought-affected area is larger in the west than in the east and that the semiarid boundary extends eastward and southward.

Selection of appropriate time scale with Boruta algorithm for regional drought monitoring using multi-scaler drought index

Spatial distribution of drought plays key role specifically in hydrological research. Drought is a complex stochastic natural hazard caused by prolonging shortage of rainfall and available water resources. The multi-scalar drought indices (based on probability distribution) are commonly used for making effective drought mitigation policies. In addition, the multi-scalar drought indices have great extent of the inaccurate determination of drought classes due to its probabilistic nature. However, the interpretation and applicability of various time scales are cumbersome for multi-scalar drought in various meteorological stations at a particular region. In this regards, accurate estimation and continuous monitoring of future drought at regional level requires a more appropriate and important time scale with respect to regions under study. In this study, we aimed to investigate the appropriate time scale for multi-scalar drought indices by using geo-reference points of meteorological stations. We used Boruta algorithm with two random forest adapters of machine learning algorithms for regionalized optimization of drought monitoring time scale. We explored the appropriate time scale for the Standardized Precipitation Temperature Index (SPTI) of 52 meteorological stations that are located across Pakistan. Results show that the significant importance of SPTI-1 (1-month time scale) for further spatial and temporal studies. That is, being high ranked and prominence, SPTI-1 has the ability to capture the characteristics of all other time scales that are in some circumstances applicable for drought characterization and classification.

SPATIAL ANALYSIS OF DROUGHT IN GROBOGAN REGENCY USING STANDARDIZED PRECIPITATION INDEX (SPI)

&lt;p&gt;&lt;span style="font-size: medium;"&gt;This study aims to determine the &lt;/span&gt;&lt;span style="font-size: medium;"&gt;spatial &lt;/span&gt;&lt;span style="font-size: medium;"&gt;distribution of drought in Grobogan &lt;/span&gt;&lt;span style="font-size: medium;"&gt;Regency &lt;/span&gt;&lt;span style="font-size: medium;"&gt;using Standardized Precipitation Index (SPI). The data used is Grobogan rainfall data for 21 years (1994-2014) at 21 rainfall&lt;/span&gt;&lt;span style="font-size: medium;"&gt;stations. The results showed that the incidence of droughts lasted for five months, from May to September. The peak of the drought occurred in August with SPI value of -1.53 to -2.51, a region with extremely dry category measuring 74394.37 hectares or 37.65% &lt;/span&gt;&lt;span style="font-size: medium;"&gt;of study &lt;/span&gt;&lt;span style="font-size: medium;"&gt;area and dry categories covering 123,191.6 hectares or 62.35% &lt;/span&gt;&lt;span style="font-size: medium;"&gt;of study &lt;/span&gt;&lt;span style="font-size: medium;"&gt;area.&lt;/span&gt;&lt;/p&gt;

Drought distribution using the standardized precipitation index: case of Gabes Basin, South Tunisia

The current research examines the temporal and spatial distribution of drought in Gabes Basin (South-Eastern Tunisia), observed over the last four decades. Monthly data of precipitation, registered in nine synoptic stations spread over the watershed for the period extending from 1977 to 2015, were used to determine the standardized precipitation index to characterize drought. The SPIs displayed results, as computed at 3, 6, 12, 24, 48, and 72 months, helped define the periods of rainfall excess and deficit, corresponding to wet and dry periods, respectively. The relevant results proved to highlight a significant variability in the SPI-associated values. On the short-term scale, the reached results proved to display a frequent fluctuation exceeding the standards, while the long-term scale relating results appeared to indicate that the dry and wet periods turned out to be rather pronounced. Furthermore, by the increasing of time scales, the extension of drought conditions will increase. On the medium and long terms, however, dry spells characterized with long periods become less frequent. Thus, the most remarkable periods in drought intensities, durations, and extensions were detected during the end of 1980 and the beginning of 2000 for different rainfall stations studied. The major drought sequence was detected to take place over the period extending from 2001 to 2005 relevant to the SPI-72 months, affecting the whole watershed. It was also found that drought occurrence in the region was mainly influenced by medium- and long-term climatic factors. Furthermore, the spatial map distribution of extreme drought events for the long term was developed displaying the variation of drought severity across the study basin.

Spatio-temporal variations in meteorology drought over the Mekong River Delta of Vietnam in the recent decades

In recent years, Mekong Delta of Vietnam is severely affected by salinity intrusion and water scarcity due to climate variability. In this study, a comprehensive analysis of meteorology drought was conducted to detect drought events using the Standardized Precipitation Index at 3-, 6-, 9- and 12-month time scale based on monthly precipitation data from 46 precipitation gauge stations for a period of 1984–2015. The aim of the study is to assess the degree of meteorology drought from 1984 to 2015 in potential crop growing areas to provide early warnings and monitor drought events to minimize their negative effects. The results indicated that meteorological drought occurred at the central provinces of the study area in the period 1985–1994, the northeastern and northwestern provinces in the period 1995–2004 and 10 recent years (2005–2014) meteorological drought shifted toward southern coastal provinces. The analyzed results also showed a tendency to decrease in frequency of drought is recorded while a tendency to increase in the spatial distribution of drought with moderate and severe droughts is recorded. Among the major droughts, 1990–1992 was evaluated the most extreme drought with 85% of the study area covered by the extreme drought with peak value of − 2.63 recorded and lasting for 29 months.

Ground and satellite based assessment of meteorological droughts: The Coello river basin case study

The spatial distribution of droughts is a key factor for designing water management policies at basin scale in arid and semi-arid regions. Ground hydro-meteorological data in neo-tropical areas are scarce; therefore, the merging of ground and satellite datasets is a promissory approach for improving our understanding of water distribution. This paper compares three monthly rainfall interpolation methods for drought evaluation. The ordinary kriging technique based on ground data, and cokriging with elevation as auxiliary variable were compared against cokriging using the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA). Twenty rain gauge stations and the 3B42V7 version of the TMPA research dataset were considered. Comparisons were made over the Coello river basin (Colombia) at 3″ spatial resolution covering a period of eight years (1998–2005). The best spatial rainfall estimation was found for cokriging using ground data and elevation. The spatial support of TMPA dataset is very coarse for a merged interpolation with ground data, this spatial scales discrepancy highlight the need to consider scaling rules in the interpolation process.

Assessing spatiotemporal variability of drought in Tihama plain, Yemen, using the standardized precipitation index (SPI) with GIS

Drought remains the most frequent and serious environmental threat in the Middle East region. In Yemen, drought has negatively affected both livelihood and sustainable development. This study aims to assess spatiotemporal variability of drought severity in the Tihama Plain—one of Yemen's most important agricultural areas, which contributes about 42 % of the country's total agricultural production. In recent years, the Tihama Plain has seen changes in the rainy season that have had a negative impact on agriculture production and water security in the area. This study uses the Standardized Precipitation Index (SPI) to conduct a temporal evaluation of the drought situation, as well as using geographic information systems (GIS) to show the spatial distribution of drought in the study area. The SPI-6 analysis results show that the years 1984, 1991, 2002–6, and 2008 were the most affected by drought during the 30-year study period (1980–2010), and show that 1991 was the worst drought year experienced by the stu...

WHAT DETERMINES THE WIDTH OF ANNUAL TREE-RINGS IN THE CENTRAL PART OF EAST-EUROPEAN PLAIN?

No tree-ring chronologies were reported so far in the International Tree Ring Data Bank for the central part of the East-European Plain. This absence is traditionally explained by the lack of motivation for tree-ring research in this area. Indeed, due to the intense anthropogenic press the old trees are rare in this region and the climatic signal embedded in the ring width is not strong and is always complex. In this study we present the new tree-ring network of 9 ring width chronologies of pine ( Pinus sylvestris ) up to 297 years long in a large region of about 450 km in diameter in the Central Russia (54–57N, 33–40E) and analyze their climatic response. Tree ring growth in the region is controlled by both temperature and precipitation of vegetation period, and all the analyzed chronologies have signifi cant correlation with summer PDSI values (with coeffi cients up to r ≤0.4). All of them were sampled after the year 2010 when a severe summer drought spread over the European part ofRussia. This allowed spatial analysis of 2010 year annual ring (and rings related to the years of other known severe droughts of 20th century) in the context of drought impact on tree growth. This study is a starting point for constructing large tree ring network for further investigation of severity and spatial distribution of droughts in European Russia in the past.

Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands.

Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800-950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period.

Resilience of Ecosystems to Climate Change

Human-induced climate change is occurring as an unprecedented rate resulting in ecosystem deterioration and biodiversity loss. Climate change exacerbates environmental hazards, ecosystem modification as well as loss of biological organisms. Anthropogenic releases of greenhouse gases, mainly CO2 has warmed the Earth’s surface. The average global temperature has risen more linearly for the last 100 year (1906-2005) by 0.74°C (.56-0.92°C); than the corresponding period (1901-2000) of 0.6°C (0.4-0.8°C). The objective of this review was to examine the potentials of ecosystems in mitigating climate change and in building resilience. A review of relevant literature was employed as possible approach to compile this document. Ethiopia is an agrarian country where agriculture is both the cause and victim to extreme climate variability like elevated temperature and precipitation fluctuation. These have resulted recurrent drought, flooding and reduction in agricultural productivity as a whole. The occurrence and spatial distribution of drought is projected to continue in the upcoming future. The effects of climate variability significantly reduced farmers’ adaptive capacity while exacerbating their vulnerability to further weather events. The current trends of ecosystem degradation could not be controlled only through protection of parks. Instead, it involves a large-scale and integrated approach addressing the whole land and sea-escapes. This large scale and integrated ecosystem management approach conserves biodiversity, builds system resilience as well as to ensures the sustainable production of ecosystem services from which the majorities of the rural poor depend on. Resilient ecosystems have a wide range of biodiversity and ecosystem services, resist and recover from extreme events more quickly and are potential to mitigate and adapt to climate change while sustaining livelihoods. Thus, ecosystem based approach through adaptation and mitigation is instrumental to maintain ecosystem health so as to sustain system resilience in the face of climate change.

Remote sensing based drought monitoring in Zimbabwe

Purpose – Drought monitoring is an important process for national agricultural and environmental planning. Droughts are normal recurring climatic phenomena that affect people and landscapes. They occur at different scales (locally, regionally, and nationally), and for periods of time ranging from weeks to decades. In Zimbabwe drought is increasingly becoming an annual phenomenon, with varying parts of the country being affected. The purpose of this paper is to analyse the spatial variations in the seasonal occurrences of drought in Zimbabwe over a period of five years. Design/methodology/approach – The Vegetation Condition Index (VCI), which shows how close the Normalized Difference Vegetation Index of the current time is to the minimum Normalized Difference Vegetation Index calculated from the long-term record for that given time, was used to monitor drought occurrence in Zimbabwe. A time series of dekadal Normalized Difference Vegetation Index, calculated from SPOT images, was used to compute seasonal VCI maps from 2005 to 2010. The VCI maps were then classified into three drought severity classes (severe, moderate, and mild) based on the relative changes in the vegetation condition from extremely bad to optimal. Findings – The results showed that droughts occur annually in Zimbabwe though, on average, the droughts are mostly mild. The occurrence and the spatial distribution of drought in Zimbabwe was also found to be random affecting different places from season to season thus the authors conclude that most parts of the country are drought prone. Originality/value – Remote sensing technologies utilising such indices as the VCI can be used for drought monitoring in Zimbabwe.