Drought Studies in Kazakhstan:
Response of Plant Growth to Surface Water Balance
Yoshihiro IIJIMA
Research Institute for Global Change
Japan Marine-Earth Science and Technology, Japanyiijima@jamstec.go.jp

Abstract
In mid-latitude semiarid grasslands, water is the primary factor limiting plant growth. Water resources
for plant growth in the grasslands of central Asia comprise snowmelt water in the spring and rainfall
during the growing season. The Kazakhstan steppe is well-known as one of the largest granaries in theEurasian continent. Soil (Chernozem) in this region is fertile, and has the potential to produce highyielding crops. However, since the hydro-climatic conditions in the region are generally severe due tolow levels of precipitation and frequent drought, water deficit is a major abiotic stress impacting onplants in this region. Therefore, crops are cultivated using not only rainfall during the growing season,
but also spring snowmelt water. In the central Asian semiarid region, snow has melted entirely by
early to mid-April, and the effect of snowmelt water on soil moisture can be clearly observed during
May. This coincides with the period when evapotranspiration exceeds precipitation due to the wet soilconditions. The seasonal nature of water availability means that the dominant crop and natural grass
species in the region have similar patterns of water use and limitations on their growth. In particular,
droughts have severe negative effects, not only on immediate plant production, but also on interannual
yield. Thus, the changes in plant growth, water use and limitations on plant growth that occur in thecentral Asian steppe on a seasonal and annual basis need to be clarified based on both in-situ andexperimental observations. In order to evaluate the impact of hydro-climatic conditions on local
surface energy balance and plant growth on a seasonal time scale, several measurements of surface
energy and water balance components and plant biomass have been conducted at a natural grassland innorthern Kazakhstan. In this presentation, we describe the changes in evapotranspiration and biomass,focusing on seasonal variations in the surface heat balance and soil moisture deficit.

Drought Studies in Mongolia: Pasture Monitoring IndicesBanzragch NANDINTSETSEG and Masato SHINODA
Arid Land Research Center, Tottori University, Japannandia@alrc.tottori-u.ac.jp

Abstract
Droughts have become widespread in the Northern Hemisphere, including Asia, notably in Mongolia.
Mongolia has a cold and arid climate that creates an extensive area of pastureland and approximately
40% of the rural population derive their livelihood from climate-dependent pastoralism. Drought is thekey factor driving livestock dynamics and human subsistence in the country; it has caused asignificant amount of damage to the economy and society. Furthermore, the increasing drought
frequency has led to problems in the farming of livestock and pasturing, and it may accelerate pasturedesertification and threaten nomadic pastoralism, therefore understanding drought processes are ofparticular concern. A number of drought indices such as Dryness index (Ped), Palmer drought severity
index (PDSI), standardized precipitation index (SPI) have been used to measure drought processes in
Mongolia. The Ped index was the commonly used index for drought assessments in the country;
however, it is based only on air temperature and precipitation. On the other hand, less attention has
been given to detect agricultural (pasture) drought and its monitoring index regardless of its negative
impact on the country. Determining an appropriate and user friendly index that reflects the direct
impact of drought on the pastureland is crucial in the country. Soil moisture is a good candidate fordrought index, reflecting recent precipitation and antecedent conditions and indicating agriculturalpotential and available water storage. In this study, drought analyses based on simulated soil moisture(Wm) derived from simple water balance model, which was developed for application in the cold, arid
regions such as Mongolia, by considering soil freezing and snow melting, was discussed. The model
performance was validated using long-term soil moisture observations (Wo), and its efficiency wasevaluated with the performance of widely used PDSI and Ped indices. Wm was more strongly
correlated with Wo (r = 0.91, p < 0.05) than PDSI (r = 0.65, p < 0.05) and Ped (r = 0.81, p < 0.05)
indices. Drought defined when Wm values (percentiles) fall continuously below a threshold value intime over a contiguous area. During the last multi-decades, drought has been found increased over thecountry. It was significantly (p < 0.05) increased particularly after 1995, in conjunction with asignificant decreasing trend in P and an increasing trend in potential evapotranspiration and resultant
decrease in pasture vegetation. Interannual anomalies of Wm and vegetation due to P during a givensummer are maintained through the freezing winter months to the following spring, and acting as aninitial condition for subsequent summer land-surface. In the interannual basis; the vegetation activity
is primarily controlled by the current year soil moisture and slightly affected by undergroundstructures stored in the root system. This concept of soil moisture and root memories would provide
practical information that can be used as an early warning system for the pasture production. In terms
of applications, the present model is a useful tool for a reliable and timely monitoring of pasturedrought, thereby providing valuable information for decision-makers and herders in the country.

Drought Studies in China
Kohei MATSUNAGA
Research Institute for Humanity and Nature, Japanmatsunaga@chikyu.ac.jp

Abstract
Drought is the greatest threat to agricultural production in China. Chinese agricultural production is acrucial issue not only for China but also for the world. Therefore, studies on agricultural droughts
have been promoted in many academic fields. Chinese drought studies are mainly classified based onfour aspects: (1) drought history, (2) drought index, (3) drought monitoring system, and (4) drought
mitigation. Previous research shows that the spatiotemporal pattern of drought disasters from 1949 to2000 differs between the east and west of China. These papers also show that heavy disaster areas
mainly lie in the north, especially to the west of Heilongjiang, the center of Inner Mongolia, and thenorth of Hebei, Shaanxi, and Ningxia, and that in the south of the country, drought disaster areas
mainly lie in five provinces (Anhui, Hubei, Hunan, Jiangxi, and Henan), Guizhou, the east of Sichuan,
and the east-central Yunnan. The distribution of drought disasters in China tends to extend toward thewest. The number of drought disasters to the north of Changjiang River has been increasing, while
those in the south have generally been decreasing. Regarding studies on agricultural drought index in
China, various methods and indices are used in evaluating rainfall, soil moisture, crop drought, cropwater requirement, and their combination. The shortage of water stored in various reservoirs isexpected to help provide a more precise index. As for the drought monitoring system, the current
remote sensing approaches to drought monitoring in China adopt several methods for effective
drought monitoring of large land areas, including thermal inertia, evapotranspiration, and thevegetation index. To mitigate the impact of drought, China has implemented irrigation, water-saving
measures, and migration regulations.

Satellite Monitoring of Drought in Central Asia and North America:
Focus on Surface Temperature Indices
Abdelmoneim A. MOHAMED and Reiji KIMURA
Arid Land Research Center, Tottori University, Japanehamir@alrc-u.ac.jp

Abstract
Central Asia and North America as part of arid regions that characterized by coupled cold and aridclimate. Over these regions drought occurs on an average of once every two or three years. The
drought dynamics in an arid, cold climate are unique in that the large amplitude of seasonal cycle inclimate/vegetation and the soil freezing/snowpack during a cold winter profoundly affect thepersistence of drought. Satellite data are widely used to monitor vegetation cover and drought episodethroughout the world. Normalized difference vegetation index (NDVI), which provides a generalmeasure of the state and health of vegetation, is one of the first remote sensing-based indicators usedfor drought detection and monitoring. Beside the conventional NDVI index Land Surface Temperature(LST) derived from thermal infrared (TIR) information serves as a proxy for assessing
evapotranspiration, vegetation water stress, soil moisture, and thermal inertia. A large number ofvegetation health and drought indices are based on the LST-NDVI space. Because droughts occur
mostly in low latitudes, several vegetation health and drought indices were developed rely on theexistence of a negative slope between the two variables (LST/NDVI). In low latitude areas, water isultimately the limiting factor for vegetation growth throughout the year, making this assumption
correct. Research carried over Gobi desert and Desert Steppe regions of central Asia points out thatthe correlations between LST and NDVI vary throughout the dryness zones. For arid zone,characterized by negative relations of the LST and NDVI, while for other dryness zone (Semi-Arid,Sub-Humid, and Humid), a relations of LST and NDVI are positive and increases from semi-arid (lowlatitude) to humid zone (high latitude).For North American continent (up to 60o N) previous research
indicates that during the summer growing season (April-September) when water is the limiting factor
for vegetation growth (the typical situation of low latitudes of North American content and during themidseason), the LST-NDVI correlation is negative. However, when energy is limiting factor forvegetation growth, as the case at higher latitudes and elevation, positive correlation exists between
LST and NDVI. It is concluded that there is a need to use empirical LST-NDVI relationships withcaution and to restrict their application to drought monitoring to areas and periods where negative
correlations are observed, namely, to conditions when water-not energy- is the primary factor limiting
vegetation growth. This review will examine available literature and new data from field andmodeling studies to evaluate performances of drought indices for further utilization of this information.

Drought Early Warning System in Asia: A Case of Mongolia
Mitsuru TSUBO
Arid Land Research Center, Tottori University, Japantsubo@alrc.tottori-u.ac.jp

Abstract
In countries where dryland farming is part of large-scale commercial agricultural systems, i.e.
Australia, South Africa and USA, drought disaster management has been developed for decades.
Meanwhile, Asian countries, e.g. India and China, produce food in small-scale
subsistence/commercial farming systems, and their food security is not as high as that of the largescale farming countries. Drought is one of the most influential factors on the small-scale farming
countries, so those countries need to develop an operational system for drought management, i.e.
drought early warning system (DEWS), to improve agricultural productivity. The DEWS consists of(i) monitoring (nowcast) of crop status, (ii) forecast of crop yield and (iii) issue of drought warning.
Recent satellite remote sensing technology allows us to monitor crop status during the growing season,and seasonal rainfall outlook is linked to yield forecasting. Farmers in most Asian countries maketheir livelihoods by carrying on crop-based/crop-livestock-mixed farming, while Mongolia is mainly
pastoral with a long history of livestock grazing. For Mongolian nomads, grassland (steppe) is themost important natural resource, and its productivity highly depends on precipitation. Their interest istherefore information on feed availability (plant biomass production) from season-to-season. Forexample, when severe drought occurs, where should the nomads take their livestock for grazing? Howmuch summer pasture production do the nomads need to leave for winter feeding? Moreover, thepasture production changes from year-to-year in association with inter-annual rainfall variability. How
do we estimate grazing capacity? Is it based on long-term average pasture production? How about thequality of vegetation in overgrazed grassland? These questions need to be answered to improve thecurrent DEWS for livestock management in Mongolia.

Future Projection of Drought in Central Asia
Kaoru TACHIIRI
Research Institute of Global Change
Japan Agency for Marine-Earth Science and Technology, Japantachiiri@jamstec.go.jp

Abstract
The 2007 Intergovernmental Panel on Climate Change report (IPCC AR4) stated that in many regions
extreme climate events are becoming increasingly frequent and that this trend will continue. However,there is significant regional difference and it depends on which kind of (e.g., climatic, agricultural orhydrological) drought is the target. The presentation will start with looking at the trends in the recentpast, which is helpful for estimating future risk. The previous studies revealed that in major part of thestudy area (i.e., China, Mongolia and Kazakhstan) precipitation does not have significant trend but
because of increasing temperature the aridity has been intensified. It was also presented that thefrequency of droughts in eastern China has slightly increased recently, but in 15-16th centuries they
had a similar level of drought frequency to that of present day. For future, the IPCC AR4 presented
that ensemble mean of climate models projected increasing precipitation and evaporation in the study
area except the western part of Kazakhstan, while soil moisture will increase in Kazakhstan and West
China but will decrease in Mongolia and East China. With these backgrounds, we are now studying
future drought risk, with special focus on the social impact, in Mongolia using process models. We
have revealed that in an earth system model (a climate model coupled with ecosystem models) in mostof 21st century vegetation activity is enhanced by increasing temperature and precipitation, but in theend of the century the temperature will excess the optimum value for photosynthesis and will
constrain the vegetation activity in the south part of Mongolia, inducing severe droughts. We also
have a future plan to study whether the result is robust for other models, as there is large inter-model
uncertainty among the climatic and vegetation models.