Drought

Desert ecosystems are characterised by large spatial and temporal variability mainly due to scarcity of moisture owing to insignificant precipitation. Desert vegetation is represented mostly by natural vegetation and least by agricultural crops. Desert plants are naturally adapted to hyper-arid climate where, rainfall is sparse and day-time temperature is very high. However, desert phenology is very sensitive to climatic parameters, particularly rainfall and temperature. Insufficient and erratic rainfall causes moisture-stress, whereas high heatflow imparts thermal-stress to vegetation. Due to higher sensitivity, slight decrease in rainfall and/or increase in temperature impart stresses on desert plants. Therefore, desert-plants suffer severely during intense droughts. Thar, the Great Indian Desert covers 446,000 km2 area in the north-western part of India and eastern part of Pakistan. The Indian portion of the Thar Desert covers 208,110 km2 area of which 61% lies in…

Northeast Thailand is the driest region in Thailand with a severe drought problem persisting for more than a decade. The impact of the drought on economy, environment and social well being is widely recognized and reported upon. Despite the importance of monitoring drought, most of previous studies have focused on drought risk and database creation. Therefore, to improve knowledge on vegetation response to precipitation at regional scale for drought monitoring, the objectives of this study were to determine the relationships between satellite-derived NDVI and rainfall over NE Thailand region, and to investigate the overall vegetation dynamics and inter-annual responses. Seven years (2000-06) of MODIS 16-day composite NDVI at 250m resolution and seven years (2000-06) of precipitation data from over 300 stations were used in this study. Spatial rainfall and NDVI anomalies as well as time lag relationships between rainfall and NDVI were analyzed. Results showed downward…

In this paper, drought status of northwestern China is evaluated using the Terra–Moderate Resolution Imaging Spectroradiometer (MODIS) data with a newly developed method called perpendicular drought index (PDI), which is defined as a line segment that is parallel with the soil line and perpendicular to the normal line of soil line intersecting the coordinate origin in the two-dimensional scatterplot of red against near infrared (NIR) wavelength reflectance. To validate the PDI in macroscale applications, quantitative evaluation of drought conditions inNingxia, Northwestern China is carried out by comparing the PDI with one ofthe well-known drought indexes, namely, temperature-vegetation index (TVX).Linear regression between ground-measured soil moisture data and the PDI andthe TVX was made. Results show that satellite based PDI and TVX hassignificant correlation with 0–20 cm averaged soil moisture obtained over themeteorological observing stations across…

This paper reports on the comparison of surface temperature and soil moisture observed by instruments onboard the Environmental Satellite (EnviSat) with simulations by an atmospheric circulation model over the period April 2005 to September 2007. The Naquriver basin has been selected as the study area, which is located on the eastern part of Tibetan Plateau. For the selected period, the PSU/NCAR meso scale model (referred to as MM5) has been employed in a coupled mode with NOAH LSm to simulate the soil moisture and surface temperature. Surface temperature and soil moisture have been retrieved from Advanced Along Track Scanning Radiometer (AATSR) and Advanced Synthetic Aperture Radar (ASAR) observations, respectively. Comparison of the simulated and satellite observed soil moisture and surface temperature showed that uncertainties in the simulated surface temperature and soil moisture are overall in agreement with each other, but are relatively large during spring and…

In order to evaluate the capability of NOAA-AVHRR data for drought monitoring in the northwest of Iran having cold semi-arid climate, a study plan was designed involving the production of normalized difference vegetation index (NDVI) and vegetation condition index (VCI) indices and correlating their values to precipitation data. Raw AVHRR images were processed and geometric and radiometric corrections were performed. Seven-day maximum NDVI maps were produced and VCI was calculated using the maximum and minimum NDVI values for the same time period. Precipitation statistics from 19 synoptic meteorological stations were collected. The study covered a five-year time period with three consecutive months in the growing season. Pearson correlation was performed to correlate NDVI and VCI values to precipitation data. Different time lag schemes were tried and the highest correlation coefficients (r values) were obtained while correlating NDVI and VCI to three-month (current…

Uruguayan economy is largely dependent, directly or indirectly, on agriculture (crops and livestock). Production in Uruguay is based on the highly fertile soils of the Pampas, an ecosystem in which native temperate and subtropical grasslands are used for livestock production or have been converted to improved pastures (grasses/legumes) and to croplands. Interannual and interseasonal climatic fluctuations in Uruguay result in high variability in crop and pasture production with frequent negative consequences on the economy.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) states that the El Niño in the Equatorial Pacific continues to sustain its moderate strength and is recently in his mature stage. Gradual decrease in sea surface temperature is expected but still within the El Niño threshold and likely to last up to June 2010. To date, Regions I, II and XII have been experiencing dry spell conditions such as drought, increased temperature, decreased rainfall and water supply which affected agricultural productions such as rice, corn and vegetables in 165,071 hectares with estimated production loss of PhP2.4B.

Source GLIDEnumber

From Oct 2009 to January 2010 Dominica southward to Trinidad experienced moderately to extremely dry conditions for the four month period. St. Lucia, Barbados, St. Vincent and the Grenadines and Grenada in particular were extremely dry. Water levels are dropping quickly in several Caribbean countries, prompting officials to limit availability and impose restrictions as the region enters its dry season.

Source: GLIDEnumber

Drought induced by El Nino has caused hunger in the departments of Choluteca, Valle La Paz, Lempira, Intibuca, El Paraiso y el Sur de Francisco Morazan. The government is supplying the communities with basic grains.

Source: www.glidenumber.net

The state of emergency has been declared for the coastal Province of Manabi as drought is affecting food security and daily lives.

Source: www.glidenumber.net