Drought

Critical Drought Analysis: Case Study of Göksu River (Turkey) and North Atlantic Oscillation Influences

by Ercan Kahya

Apparent loss of Vibrio vulnificus in North Carolina oysters coincides with drought-induced increase in salinity

by Brett Froelich

Late Holocene Paleoclimate Reconstruction and Long-Term Human Response in the Region of Timbuktu, Mali (West Africa): Interdisciplinary collaboration in the study of Lake Faguibine and the drought-afflicted populations

by Douglas Park 

Co-Authored with R. McIntosh, R. Smith, P. Douglas, C. Warren and P. Coutros. Yale Climate and Energy Institute Multidisciplinary Grant for climate and archaeology research in Timbuktu. Granted 2009 - ongoing

This interdisciplinary project seeks to integrate climatological, remote sensing, geomorphological and archaeological... more This interdisciplinary project seeks to integrate climatological, remote sensing, geomorphological and archaeological research into a cohesive study of long-term climate change over the past 5000 years at the border between the Sahara and the Sahel at Timbuktu, which is part of the Middle Niger hydraulic system. Understanding how humans have responded to Late Holocene climates in this region, to their long-term trends and abrupt excursions, will provide insight into the types of social institutions employed by the local populations that sought effectively to deal with the unpredictability of their physical world.

Seasonal and Location Independence of Drought Index (PDSI) for Lower Niobrara River Basin

by Baburao Kamble

The socioeconomics of food crop production and climate change vulnerability: a global scale quantitative analysis of how grain crops are sensitive to drought

by Simon Gosling

Many studies warn that climate change may undermine global food security. Much work on this topic focuses on modelling... more Many studies warn that climate change may undermine global food security. Much work on this topic focuses on modelling crop-weather interactions but these models do not generally account for the ways in which socio-economic factors influence how harvests are affected by weather. To address this gap, this paper uses a quantitative harvest vulnerability index based on annual soil moisture and grain production data as the dependent variable in a Linear Mixed Effects model with national scale socio-economic data as independent variables for the period 1990–2005. Results show that rice, wheat and maize production in middle income countries were especially vulnerable to droughts. By contrast, harvests in countries with higher investments in agriculture (e.g. higher amounts of fertilizer use) were less vulnerable to drought. In terms of differences between the world’s major grain crops, factors that made rice and wheat crops vulnerable to drought were quite consistent, while those of maize crops varied considerably depending on the type of region. This is likely due to the fact that maize is produced under very different conditions worldwide. One recommendation for reducing drought vulnerability risks is coordinated development and adaptation policies, including institutional support that enables farmers to take proactive action.

Analyzing precipitationsheds to understand the vulnerability of rainfall dependent regions

by Sturle Hauge Simonsen

Full reference: Keys, P. W., van der Ent, R. J., Gordon, L. J., Hoff, H., Nikoli, R., and Savenije, H. H. G. 2012. Analyzing precipitationsheds to understand the vulnerability of rainfall dependent regions, Biogeosciences, 9, 733-746, doi:10.5194/bg-9-733-2012

It is well known that rivers connect upstream and downstream ecosystems within watersheds. Here we describe the... more It is well known that rivers connect upstream and downstream ecosystems within watersheds. Here we describe the concept of precipitationsheds to show how upwind terrestrial evaporation source areas contribute moisture for precipitation to downwind sink regions.

We illustrate the importance of upwind land cover in precipitationsheds to sustain precipitation in critically water stressed downwind areas, specifically dryland agricultural areas. We first identify seven regions where rainfed agriculture is particularly vulnerable to reductions in precipitation, and then map their precipitationsheds.

We then develop a framework for qualitatively assessing the vulnerability of precipitation for these seven agricultural regions. We illustrate that the sink regions have varying degrees of vulnerability to changes in upwind evaporation rates depending on the extent of the precipitationshed, source region land use intensity and expected land cover changes in the source region.

The effect of drought on Oligochaeta communities in small woodland streams

by Jacek Koszałka

Elzbieta Dumnicka, Jacek Koszałka 2005. Biologia - section Zoology

Volume 60, 2005, No. 2

Giuggiola A, Kuster TM, Saha S, 2010. Drought-induced mortality of Scots Pines at the southern limits of its distribution in Europe: causes and consequences. iForest 3: 95-97 [online: 2010-07-15]

by Somidh Saha

Yield enhancement of droughted wheat by film antitranspirant application: rationale and evidence

by Peter Kettlewell

Hanzai jiushi deng xia yu» Siccità, si aspetta solo la pioggia. Costruzione sociale del rischio in un villaggio rurale cinese

by Andrea Pia

O processo de desertificação e os riscos de sua ocorrência no Brasil

by Philip Fearnside

Fearnside, P.M. 1979.  O processo de desertificação e os riscos de sua ocorrência no Brasil. Acta Amazonica 9(2): 393 400.

Evaluation of SPOT – VEGETATION derived global vegetation assessment product for near-real time drought monitoring over India

by Vinay Sehgal

R. Jaishanker, V.K. Sehgal, T. Senthivel, and V.K. Dadhwal

Proceedings of the National Academy of Sciences, India
Vol. 76, B, Part I (January to March) 2006

An Assessment of Municipal Drought Contingency Planning in Texas

by Texas State PA Applied Research Projects

Billingsley, Bill G., "An Assessment of Municipal Drought Contingency Planning in Texas" (2002). Applied Research Projects, Texas State University-San Marcos. Paper 62.
http://ecommons.txstate.edu/arp/62

Water availability is an important environmental issue in the United States. Since water is becoming more a limited... more Water availability is an important environmental issue in the United States. Since water is becoming more a limited natural resource, water policy will be a primary source of controversy, specifically during periods of drought. Recent widespread droughts have raised concerns about our nation’s vulnerability to periods of water shortages. It is imperative that public administrators of municipal water supply systems develop drought contingency plans that deal with water shortages in a timely and systematic manner because droughts are a normal part of the climate for most regions, especially for Texas.

The purpose of this research is twofold. The first purpose is to explain the ideal components of a municipal drought contingency plan. The elements include public involvement, drought response triggering criteria, successive stages of response, drought response management measures, enforcement and plan adoption. The next objective is to assess the drought contingency plans of retail public water suppliers submitted to the Texas Commission on Environmental Quality (TCEQ) to determine which retail public water suppliers utilized the model drought contingency plan and how close all the plans met the ideal components. The overall assumption of this research is that the model drought contingency plan developed by the TCEQ is an effective tool for retail public water suppliers in Texas to aid them in meeting the regulatory components of drought contingency plans.

The first portion of this research examines, from a national level, the concept of drought, drought impacts, future impacts facing municipal public water suppliers, problems with traditional drought planning, drought policy, and lessons learned from previous droughts. A conceptual framework for a municipal drought contingency plan is developed from the review of available literature. The purpose of the review is to explain the components of an ideal plan.

The paper later focuses on Texas, the setting for this research. A brief overview of Texas droughts and projections are presented. A description is provided for both the model drought contingency plan and the municipal drought contingency plans selected for assessment.

The later part of the paper discusses the methodology used to assess the municipal drought contingency plans submitted to the TCEQ by retail public water suppliers in Texas. Content analysis is used to determine which municipal public water suppliers utilized the TCEQ model drought contingency plan in developing their plans and which did not. After determining which suppliers utilized the model, content analysis is further used for each of the drought contingency plans to determine which ideal components are included in all of the plans. A discussion of how the practical ideal type of a municipal drought contingency plan is operationalized into measurable items for assessment is provided. The findings of the analysis confirm that the model plan in Texas is an effective tool for retail public water suppliers in meeting the required components of drought contingency plans.

The paper concludes with a summary of the research findings in relation to the practical ideal type of the model drought contingency plan in Texas and concludes with recommendations and suggestions for additional research.

Naturalizing Disaster: from Drought to Famine in South India

by Kathleen Morrison

Book chapter in "Environmental Disaster and the Archaeology of Human Response," Anthropological Papers No. 7, G. Bawden and R.M. Reycraft (eds.), Maxwell Museum of Anthropology, 2000.

Observed drought and wetness trends in Europe: an update

by Isabella Bordi

Martin StPaul N, J-M Limousin, J Rodriguez-Calcerrada, J Ruffault, S Rambal, MG Letts & L Misson. In press. Photosynthetic sensitivity to drought varies among populations of Quercus ilex along a rainfall gradient. Functional Plant Biology. 39(1):25-37

by Matthew G Letts

Drought frequency and intensity are expected to increase in the Mediterranean as a consequence of global climate... more Drought frequency and intensity are expected to increase in the Mediterranean as a consequence of global climate change. To understand how photosynthetic capacity responds to long-term water stress, we measured seasonal patterns of stomatal (SL), mesophyll (MCL) and biochemical limitations (BL) to net photosynthesis (Amax) in three Quercus ilex (L.) populations from sites differing in annual rainfall. In the absence of water stress, stomatal conductance (gs), maximum carboxylation capacity (Vcmax), photosynthetic electron transport rate (Jmax) and Amax were similar among populations. However, as leaf predawn water potential (Ψl,pd) declined, the population from the wettest site showed steeper declines in gs, Vcmax, Jmax and Amax than those from the drier sites. Consequently, SL, MCL and BL increased most steeply in response to decreasing Ψl,pd in the population from the wettest site. The higher sensitivity of Amax to drought was primarily the result of stronger stomatal regulation of water loss. Among-population differences were not observed when gs was used instead of Ψl,pd as a drought stress indicator. Given that higher growth rates, stature and leaf area index were observed at the wettest site, we speculate that hydraulic architecture may explain the greater drought sensitivity of this population. Collectively, these results highlight the importance of considering among-population differences in photosynthetic responses to seasonal drought in large scale process-based models of forest ecosystem function.

Assessment of Agricultural Drought Using MODIS Derived Normalized Difference Water Index

by Vinay Sehgal

A. Chakraborty, V. K. Sehgal
Journal of Agricultural Physics, Vol. 10, pp. 28-36 (2010)

Remote sensing index NDVI or its derivatives are used for agricultural drought monitoring and early warning at... more Remote sensing index NDVI or its derivatives are used for agricultural drought monitoring and early warning at regional scale worldwide. Studies have shown that NDVI has lagged response to rainfall deficit. Moreover the red band used in NDVI is highly absorbed by crop canopy in comparison to short infrared which has high penetration so thus there remains a discrepancy between the levels of penetration in crop canopy. In contrast, Normalized Difference Water Index (NDWI) uses both the bands in near infrared region and is very sensitive to liquid water content of vegetation canopy and so rainfall. So this study was conducted to evaluate the sensitivity of NDWI in detecting and monitoring the agricultural drought in comparison with NDVI. In the study three indices of NDVI, NDWI5 and NDWI6 were computed using MODIS 09A1 surface reflectance product from June to October of 2002 (drought year) and 2003 (normal year) for the state of Rajasthan. NOAA Climate Prediction Centre (CPC) rainfall product was used and averaged at district level. The NDWI5 showed very strong relation with current rainfall than NDWI6 and weakest was shown by NDVI. The relation of NDVI with lagged rainfall was much better than with current rainfall. The spatial comparison of changes in NDVI and NDWI5 between the drought year (2002) and normal year (2003) for each 8 days composite showed that NDWI5 very well picks up the intensity and extent of drought. Study also showed that NDWI5 is more sensitive to agricultural drought than NDWI6. The study recommends use of NDWI5 for better early detection and monitoring of agricultural drought in operational drought management programmes.

Spatio-temporal Trends of Standardized Precipitation Index for Meteorological Drought Analysis across Agroclimatic Zones of India

by Vinay Sehgal

SOMNATH JHA, V.K. SEHGAL, R. C. RAGHAVA
Presneted at TROPMET-2010, Calcutta

1. Introduction:

Drought is a normal part of climate of India and every year it affects one or the other... more 1. Introduction:

Drought is a normal part of climate of India and every year it affects one or the other State. Droughts, like other meteorological phenomena, have spatial and temporal characteristics that vary significantly from one region to another. The understanding of the spatio-temporal trends of meteorological drought helps in undertaking informed decisions on their preparedness and mitigation measures. Though no significant trends have been reported in the Indian Summer Monsoon Rainfall (IMSR) over long periods, the spatio-temporal trends in drought indices reveals the anomaly in rainfall across region over different time scales which may be related to climate change induced extreme rainfall events. So, a study was carried out to compute spatio-temporal trends in Standardized Precipitation Index (SPI), an index of rainfall anomaly, using gridded monthly rainfall dataset of CRU TS 3.0 for 1951 – 2006 period for Indian landmass and the results are reported here.

2. Methodology:

SPI is simply the difference of standardized precipitation from its mean for a specified time period divided by the standard deviation. As precipitation is typically not normally distributed for accumulation periods of 12 months or less, SPI overcomes this disadvantage by fitting an incomplete gamma distribution and then transforming it to normal distribution. Negative values of SPI due to less than normal rainfall indicate dryness while SPI less than -1 indicate drought. Delineation of homogeneous regions for climate change / trend analysis has been a debatable matter due to unwise delineation of the homogeneous regions basing on single climatic variable, mostly the isohyets. Therefore, in this study 14 Agroclimatic Zones (ACZs) of India were selected for SPI trend analysis as homogeneous regions (Fig 1) due to commonality of climatic parameters and their extremes, soil types and water resources. The results of drought trends at ACZ level also can be directly translated into plans for agricultural sector. SPI were computed for individual months (June, July, August and September) and for whole Indian summer monsoon duration (June-July-August-September i.e. JJAS). Mean SPIs of various ACZs for the individual months and JJAS over 56 years period were analyzed for temporal trend using Mann Kendall test and regional temporal trend across all ACZ together using Regional Kendall test.

3. Results:

Significant temporal trends in monthly & JJAS SPI at 10% or lower level of significance were observed for ACZ4 (Middle Gangetic plains), ACZ5 (Upper Gangetic plains), ACZ6 (Trans Gangetic plains), ACZ7 (Eastern plateau and hills), ACZ8 (Central plateau and hills), ACZ12 (West coast) and ACZ14 (Western dry) regions. Rest of the ACZs did not show any significant trend in SPI for the 56 years study period. In ACZ4, SPI showed consistently negative trend for JUN, JUL, AUG and JJAS, whereas in ACZ5, SPI showed significant negative trend for JUL, AUG & JJAS. SPI showed significant negative trend in SEP & JJAS for ACZ7, AUG & JJAS in ACZ8, JUL in ACZ12 and AUG in ACZ14. On the other hand, a significantly positive trend in SPI was observed in JUN in ACZ6, ACZ8, and ACZ12.
The analysis of temporal trends in SPI for all ACZs taken together using Regional Kendall test showed a significant positive trend in JUN SPI, while significant negative trends in SPI were observed for JUL, AUG and JJAS across India. No significant trend was observed for SEP SPI. The rate of increase in JUN SPI was 0.75E-02 per year, while the rate of change of SPI for JUL, AUG, & JJAS was -0.76E-02, -0.54E-02, and -0.65E-02 per year, respectively.

4. Conclusions:

Among the different ACZ of India, there is an increase in probability of meteorological drought hazard in ACZ4, ACZ5, ACZ7 and ACZ8 covering the States of Bihar, Uttar Pradesh, Madhya Pradesh, Orissa and Eastern Rajasthan. Results also points to significant decreasing trend in rainfall of these regions for different months as well as for JJAS monsoon period. In the dry western parts of India (Western Rajasthan and Gujarat), which are traditionally water scare regions, there is no change in probability of occurrence of meteorological drought.
Overall for India as a whole, there is an increase in probability of meteorological drought in future due to decreasing trend in rainfall for JJAS period. The months of July and August will become drier and while June month will become wetter. This change in rainfall distribution towards early period and overall drier months of July, August have important implication for the productivity of main crop season of India thus impacting its food security negatively.

Drought disaster challenges and mitigation in India: strategic appraisal

by Vinay Sehgal

Anil K. Gupta, Pallavee Tyagi and Vinay K. Sehgal
CURRENT SCIENCE, VOL. 100, NO. 12, 1795 - 1806, 25 JUNE 2011

DROUGHT is a complex, slow-onset phenomenon of ecological
challenge that affects people more than any other... more DROUGHT is a complex, slow-onset phenomenon of ecological
challenge that affects people more than any other natural hazards by causing serious economic, social and environmental losses in both developing and developed countries. The period of unusual dryness (i.e. drought) is a normal feature of the climate and weather system in semi-arid and arid regions of the tropics, which covers more than one-third of the land surface and is vulnerable to drought and desertification. A drought is an extended period where water availability falls below the statistical requirements for a region. Drought is not a purely physical phenomenon, but instead is an interplay between natural water availability and human demands for water supply. There is no universally accepted definition of drought. It is generally considered to be occurring when the principal monsoons, i.e. southwest monsoon and northeast monsoon, fail or are deficient or scanty. Monsoon failure causing crop failure, drying up ecosystems and shortage of drinking water results in undue hardship to the rural and urban communities. Although droughts are still largely unpredictable; they are a recurring feature of the climate. Drought varies with regard to the time of occurrence, duration, intensity and extent of the area affected from year to year4. Land abuse during periods of good rains and its continuation during periods of deficient rainfall is the combination that contributes to desertification. Dry regions in India include about 94 mha and about 300 million people (one-third of India’s population) live in these areas; more than 50% of the region is affected by drought once every four years6. Different countries and states have developed codes, manuals, procedures, processes and policies for monitoring and management of drought with varying understanding. Over the years, India has developed a fairly elaborate governance system of institutionalized drought monitoring, declaration and mitigation at different levels. India’s response to the need for enhanced drought management has contributed to overall development. For example, the drought of 1965–1967 encouraged the ‘green revolution’, after the 1972 drought employment generation programmes were developed for the rural poor; the 1987–1988 drought relief effort focused on preserving the quality of life.

Analysis of Meteorological Drought at New Delhi using SPI

by Vinay Sehgal

S. Pradhan , V.K. Sehgal, D.K. Das and R. Singh
Journal of Agrometeorology 13 (1): 68-71 (June 2011)