Multi-scalar Drought Index Research Articles

Establishing Relationships between Drought Indices and Wildfire Danger Outputs: A Test Case for the California-Nevada Drought Early Warning System

Relationships between drought indices and fire danger outputs are examined to (1) incorporate fire risk information into the National Integrated Drought Information System California–Nevada Drought Early Warning System and (2) provide a baseline analysis for application of drought indices into a fire risk management framework. We analyzed four drought indices that incorporate precipitation and evaporative demand (E0) and three fire indices that reflect fuel moisture and potential fire intensity. Seasonally averaged fire danger outputs were most strongly correlated to multi-scalar drought indices that use E0 (the Evaporative Demand Drought Index (EDDI) and the Standardized Precipitation Evapotranspiration Index (SPEI)) at approximately annual time scales that reflect buildup of antecedent drought conditions. Results indicate that EDDI and SPEI can inform seasonal fire potential outlooks at the beginning of summer. An E0 decomposition case study of conditions prior to the Tubbs Fire in Northern California indicate high E0 (97th percentile) driven predominantly by low humidity signaled increased fire potential several days before the start of the fire. Initial use of EDDI by fire management groups during summer and fall 2018 highlights several value-added applications, including seasonal fire potential outlooks, funding fire severity level requests, and assessing set-up conditions prior to large, explosive fire cases.

A drought index: The standardized precipitation evapotranspiration runoff index

Based on the principles underlying the calculation of the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI), this study selects precipitation, temperature, relative humidity, sunshine hours, wind speed and runoff data to develop a multi-scalar drought index, the standardized precipitation evapotranspiration runoff index (SPERI), using methods such as Penman-Monteith and Copula. This index is applied along with the SPI and SPEI to Yunnan Province of China. The results show that the changes in the SPERI are close to those in the SPI and SPEI. They are well correlated and can all reflect drought conditions. In addition, comparisons among these three drought indexes and the actual extreme drought during September 2009–August 2010 showed that the SPERI was superior to the SPI and SPEI and that the 3-month SPERI assessment was the most accurate. Therefore, the SPERI can be used to analyze, assess and forecast drought conditions in different areas as well as to assess the impacts of climate change on drought.

Future drought risk in Africa: Integrating vulnerability, climate change, and population growth

Drought risk refers to the potential losses from hazard imposed by a drought event, and it is generally characterized as a function of vulnerability, hazard, and exposure. In this study, drought risk is assessed at a national level across Africa, and the impacts of climate change, population growth, and socioeconomic vulnerabilities on drought risk are investigated. A rigorous framework is implemented to quantify drought vulnerability considering various sectors including economy, energy and infrastructure, health, land use, society, and water resources. Multi-model and multi-scenario analyses are employed to quantify drought hazard using an ensemble of 10 regional climate models and a multi-scalar drought index. Drought risk is then assessed in each country for 2 climate emission pathways (RCP4.5 and RCP8.5), 3 population scenarios, and 3 vulnerability scenarios during three future periods between 2010 and 2100. Drought risk ratio is quantified, and the role of each component (i.e. hazard, vulnerability, and exposure) is identified, and the associated uncertainties are also characterized. Results show that drought risk is expected to increase in future across Africa with varied rates for different models and scenarios. Although northern African countries indicate aggravating drought hazard, drought risk ratio is found to be highest in central African countries as a consequent of vulnerability and population rise in that region. Results indicate that if no climate change adaptation is implemented, unprecedented drought hazard and risk will occur decades earlier. In addition, controlling population growth is found to be imperative for mitigating drought risk in Africa (even more effective than climate change mitigation), as it improves socioeconomic vulnerability and reduces potential exposure to drought.

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.

A Probabilistic Weighted Joint Aggregative Drought Index (PWJADI) criterion for drought monitoring systems

Drought is a complex natural hazard. Its several adverse impacts are prevailing in almost all climatic zones around the world. In this regards, drought monitoring and forecasting play a vital role in making drought mitigation policies. Therefore, several drought monitoring tools based on probabilistic models had been developed for precise and accurate inferences of drought severity and its effects. However, risk of inaccurate determination of drought classes always exists in probabilistic models. To overcome this issue, we proposed a new system based Probabilistic Weighted Joint Aggregative Drought Index (PWJADI) criterion for three multi-scalar drought indices, namely Standardized Precipitation Index (SPI), Standardized Precipitation Temperature Index (SPTI), and Standardized Precipitation Evapotranspiration Index (SPEI) at one-month time scale. By the basic assumption of the Markov chain, the PWJADI is based on the temporal switched weights that are propagated from the transition probability matrix of each temporal classification of drought index. Application of the proposed method is made for three meteorological stations of Pakistan. We found that our proposed model has ability to restructure the drought classes by capturing and bending the information from the historical behaviour of each drought class. Consequently, to make accurate and precise drought mitigation policies, the proposed method may integrate into effective drought monitoring systems.

Drought Sensitiveness on Forest Growth in Peninsular Spain and the Balearic Islands

Drought is one of the key natural hazards impacting net primary production and tree growth in forest ecosystems. Nonetheless, tree species show different responses to drought events, which make it difficult to adopt fixed tools for monitoring drought impacts under contrasting environmental and climatic conditions. In this study, we assess the response of forest growth and a satellite proxy of the net primary production (NPP) to drought in peninsular Spain and the Balearic Islands, a region characterized by complex climatological, topographical, and environmental characteristics. Herein, we employed three different indicators based on in situ measurements and satellite image-derived vegetation information (i.e., tree-ring width, maximum annual greenness, and an indicator of NPP). We used seven different climate drought indices to assess drought impacts on the tree variables analyzed. The selected drought indices include four versions of the Palmer Drought Severity Index (PDSI, Palmer Hydrological Drought Index (PHDI), Z-index, and Palmer Modified Drought Index (PMDI)) and three multi-scalar indices (Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI), and Standardized Precipitation Drought Index (SPDI)). Our results suggest that—irrespective of drought index and tree species—tree-ring width shows a stronger response to interannual variability of drought, compared to the greenness and the NPP. In comparison to other drought indices (e.g., PDSI), and our results demonstrate that multi-scalar drought indices (e.g., SPI, SPEI) are more advantageous in monitoring drought impacts on tree-ring growth, maximum greenness, and NPP. This finding suggests that multi-scalar indices are more appropriate for monitoring and modelling forest drought in peninsular Spain and the Balearic Islands.

Contribution of Land Surface Temperature (TCI) to Vegetation Health Index: A Comparative Study Using Clear Sky and All-Weather Climate Data Records

The Vegetation Health Index (VHI) is widely used for monitoring drought using satellite data. VHI depends on vegetation state and thermal stress, respectively assessed via (i) the Vegetation Condition Index (VCI) that usually relies on information from the visible and near infra-red parts of the spectrum (in the form of Normalized Difference Vegetation Index, NDVI); and (ii) the Thermal Condition Index (TCI), based on top of atmosphere thermal infrared (TIR) brightness temperature or on TIR-derived Land Surface Temperature (LST). VHI is then estimated as a weighted average of VCI and TCI. However, the optimum weights of the two components are usually not known and VHI is usually estimated attributing a weight of 0.5 to both. Using a previously developed methodology for the Euro-Mediterranean region, we show that the multi-scalar drought index (SPEI) may be used to obtain optimal weights for VCI and TCI over the area covered by Meteosat satellites that includes Africa, Europe, and part of South America. The procedure is applied using clear-sky Meteosat Climate Data Records (CDRs) and all-sky LST derived by combining satellite and reanalysis data. Results obtained present a coherent spatial distribution of VCI and TCI weights when estimated using clear- and all-sky LST. This study paves the way for the development of a future VHI near-real time operational product for drought monitoring based on information from Meteosat satellites.

Towards a theoretical understanding of multiscalar drought indices based on the relationship between precipitation and standardized precipitation index

This study reports a theoretical understanding of multiscalar drought indices based on the relationship between precipitation and Standardized Precipitation Index (SPI). To unveil the multiscalar structure of precipitation, the advanced technique of wavelet decomposition is systematically applied to dissect the precipitation into a number of orthogonal components according to different time scales. A case study over Southwest China demonstrated a time lag or a synchronous correlation, depending on the time scale, between precipitation and the SPI, with precipitation always leading the SPI. The delayed response of the SPI to precipitation becomes more significant as the temporal scale increases, while the lead-lag effect vanishes at the shortest time scales. Most importantly, the SPI at a specific time responds primarily to the corresponding precipitation component, regardless of the contribution of its variance to the total variability. The conclusions obtained in the case study are further strengthened by global analysis. Moreover, the lag time between the SPI and precipitation at longer time scales has great geographic diversity worldwide, in contrast to shorter time scales, which have spatially uniform response times irrespective of site. In addition, we also clarify two core concepts that are easily confused, time scale and lag time. Finally, our study highlights the prominent utility of a multiscalar drought index to detect drought for a wide range of time scales compared to other metrics with rigid time scale, owing to the multistructural property of precipitation that results in multiscalar drought.

Apprehensive Drought Characteristics over Iraq: Results of a Multidecadal Spatiotemporal Assessment

Drought is an extreme climate phenomenon that happens slowly and periodically threatens the environmental and socio-economic sectors. Iraq is one of the countries in the Middle East that has been dealing with serious drought-related issues in the 21st century. Here, we investigate meteorological drought across Iraq from 1948 to 2009 at 0.25° spatial resolution. The Standardized Precipitation Evapotranspiration Index (SPEI) has been utilized as a multi-scalar drought index accounting for the effects of temperature variability on drought. Four of the main characteristics of drought including extent, intensity, frequency and duration are studied and the associated spatiotemporal patterns are investigated for each case. Results revealed a significant drought exacerbation over Iraq during the period of 1998–2009. Two significant drought periods of 1998–1999 and 2007–2008 are identified during which severe to extreme droughts covered about 87% and 82% of Iraq, respectively. Analyzing the trends of drought intensity reveals that the central and southwestern parts of Iraq have experienced aggravated intensifying patterns among other regions. In general, droughts are found to be more frequent but shorter at the western, central and southeastern parts of Iraq.

Drought and Spatiotemporal Variability of Forest Fires Across Mexico

Understanding the spatiotemporal links between drought and forest fire occurrence is crucial for improving decision-making in fire management under current and future climatic conditions. We quantified forest fire activity in Mexico using georeferenced fire records for the period of 2005–2015 and examined its spatial and temporal relationships with a multiscalar drought index, the Standardized Precipitation-Evapotranspiration Index (SPEI). A total of 47 975 fire counts were recorded in the 11-year long study period, with the peak in fire frequency occurring in 2011. We identified four fire clusters, i.e., regions where there is a high density of fire records in Mexico using the Getis-Ord G spatial statistic. Then, we examined fire frequency data in the clustered regions and assessed how fire activity related to the SPEI for the entire study period and also for the year 2011. Associations between the SPEI and fire frequency varied across Mexico and fire-SPEI relationships also varied across the months of major fire occurrence and related SPEI temporal scales. In particular, in the two fire clusters located in northern Mexico (Chihuahua, northern Baja California), drier conditions over the previous 5 months triggered fire occurrence. In contrast, we did not observe a significant relationship between drought severity and fire frequency in the central Mexico cluster, which exhibited the highest fire frequency. We also found moderate fire-drought associations in the cluster situated in the tropical southern Chiapas where agriculture activities are the main causes of forest fire occurrence. These results are useful for improving our understanding of the spatiotemporal patterns of fire occurrence as related to drought severity in megadiverse countries hosting many forest types as Mexico.

Weakening sensitivity of global vegetation to long-term droughts

Droughts have dramatic direct and indirect impacts on vegetation and terrestrial ecosystem stability, including decreases in growth and subsequent decreases in CO2 absorption. Although much research has been carried out on the response of vegetation to droughts, it remains unclear whether biomes are becoming more resistant or more vulnerable to drought. In this study, we used the Standardized Precipitation Evapotranspiration Index (SPEI, a multiscalar drought index) and the Normalized Difference Vegetation Index (NDVI, an indicator of vegetation growth) to detect the sensitivity of vegetation growth to droughts across 12–24 month timescales and to detect the change in this sensitivity over recent decades. We found that vegetation growth was most sensitive to 17–18 month droughts in water-limited regions, implying pronounce legacy effects from water conditions in previous years. In addition, we detected reduced coupling between drought and vegetation growth, probably caused by release moisture stress in water limited areas. Meanwhile, we observed a shortening of drought timescale to which vegetation most sensitively responded from an average of 18.1 to 17.2 months, suggesting the weakening of the drought legacy effect on vegetation growth. Results of this study contribute to the overall understanding of the resistance and resilience of ecosystems to drought conditions.

A Novel Multi-Scalar Drought Index for Monitoring Drought: the Standardized Precipitation Temperature Index

Nowadays human beings are facing many environmental challenges because of frequently occurring drought hazards. Several adverse impacts of drought hazard are continued in many parts of the world. Drought has a substantial influence on water resources and irrigation. It may effect on the country’s environment, communities, and industries. Therefore, it is important to improve drought monitoring system. In this paper, we proposed a novel method – Standardized Precipitation Temperature Index (SPTI) for drought monitoring that utilize the regional tempreature. We compared the performance of our proposed drought index – SPTI with commonly used drought indices (i.e., Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI)) for 17 meteorological stations of Khyber Pakhtunkhwa (KPK) province (Pakistan) that have both extreme (arid and humid) climatic environment. We found that SPTI is strongly correlated with SPI and performed better than SPEI in low temperature regions for drought monitoring. In summary, SPTI is recommended for detecting and monitoring the drought conditions over different time scales.

Assessing the role of drought events on wildfires in the Iberian Peninsula

Southern European countries are particularly affected by summer wildfires and drought events. The occurrence of extreme meteorological conditions during preceding and contemporaneous months amplifies the risk of summer wildfires.The main scope of this study was to investigate the impact of drought periods on burned areas in the Iberian Peninsula. This will be achieved through the comparison of time series of two widely used multi-scalar drought indices (SPI and SPEI) calculated for each province and then associated with the time series of the standardized logarithm of normalized burned areas during the fire summer season. The SPI and SPEI were both calculated for the time scales spanning between 2 to 12 months and for each month from January to August, between 1980 and 2005. Based on the regression analysis between drought indicators and burned areas, the months that present lowest errors were identified for each province. From the obtained results two main conclusions were reached: (i) the association between drought and fires is a local scale process and should be analyzed at the province or sub-province level rather than at the country or continental level; (ii) the relation between wildfires and drought is better explained by the influence of the spring precipitation on the central sector and by the influence of temperature and precipitation during summer on most of the Portuguese provinces.

Drought assessment using standardised precipitation evaporation index and its association with southern oscillation index in the Northwestern Bangladesh

The trend of drought in the northwestern region of Bangladesh was analysed in this study. To analyse the trend of the multiscalar drought index standardised precipitation evaporation index (SPEI), Mann-Kendall's test and Sen's slope estimator have been used. Assessment of variability of SPEI was conducted by means of the continuous wavelet power spectrum. Significant variability of 6 month scale SPEI was found at 16 to 32 months and 32 to 64 month period from almost 1987 to 2008. To grasp the influence of the southern oscillation index (SOI) on a 6 month scale SPEI, statistical tool wavelet coherence (WTC) has been used. Significant wavelet coherency was observed between SOI and 6 month SPEI at higher periodicity and short time span. The outcomes from this study could assist engineers of agriculture and the water resources sector to establish strategies in Northwestern Bangladesh.

The role of drought on wheat yield interannual variability in the Iberian Peninsula from 1929 to 2012.

The production of wheat in the Iberian Peninsula is strongly affected by climate conditions being particularly vulnerable to interannual changes in precipitation and long-term trends of both rainfall and evapotranspiration. Recent trends in precipitation and temperature point to an increase in dryness in this territory, thus highlighting the need to understand the dependence of wheat yield on climate conditions. The present work aims at studying the relation between wheat yields and drought events in the Iberian Peninsula, using a multiscalar drought index, the standardized precipitation evapotranspiration index (SPEI), at various timescales. The effects of the occurrence of dry episodes on wheat yields were analyzed, on regional spatial scale for two subperiods (1929-1985 and 1986-2012). The results show that in western areas, wheat yield is positively affected by dryer conditions, whereas the opposite happens in eastern areas. The winter months have a bigger influence in the west while the east is more dependent on the spring and summer months. Moreover, in the period of 1986-2012, the simultaneous occurrence of low-yield anomalies and dry events reaches values close to 100% over many provinces. Results suggest that May and June have a strong control on wheat yield, namely, for longer timescales (9 to 12months). A shift in the dependence of wheat yields on climatic droughts is evidenced by the increase in the area with positive correlation and the decrease in area with negative correlation between wheat yields and SPEI, probably due to the increase of dry events.

Effects of Recent Minimum Temperature and Water Deficit Increases on Pinus pinaster Radial Growth and Wood Density in Southern Portugal

Western Iberia has recently shown increasing frequency of drought conditions coupled with heatwave events, leading to exacerbated limiting climatic conditions for plant growth. It is not clear to what extent wood growth and density of agroforestry species have suffered from such changes or recent extreme climate events. To address this question, tree-ring width and density chronologies were built for a Pinus pinaster stand in southern Portugal and correlated with climate variables, including the minimum, mean and maximum temperatures and the number of cold days. Monthly and maximum daily precipitations were also analyzed as well as dry spells. The drought effect was assessed using the standardized precipitation-evapotranspiration (SPEI) multi-scalar drought index, between 1 to 24-months. The climate-growth/density relationships were evaluated for the period 1958-2011. We show that both wood radial growth and density highly benefit from the strong decay of cold days and the increase of minimum temperature. Yet the benefits are hindered by long-term water deficit, which results in different levels of impact on wood radial growth and density. Despite of the intensification of long-term water deficit, tree-ring width appears to benefit from the minimum temperature increase, whereas the effects of long-term droughts significantly prevail on tree-ring density. Our results further highlight the dependency of the species on deep water sources after the juvenile stage. The impact of climate changes on long-term droughts and their repercussion on the shallow groundwater table and P. pinaster’s vulnerability are also discussed. This work provides relevant information for forest management in the semi-arid area of the Alentejo region of Portugal. It should ease the elaboration of mitigation strategies to assure P. pinaster’s production capacity and quality in response to more arid conditions in the near future in the region.

Drought impacts on vegetation activity in the Mediterranean region: An assessment using remote sensing data and multi-scale drought indicators

The present work analyzes the drought impacts on vegetation over the entire Mediterranean basin, with the purpose of determining the vegetation communities, regions and seasons at which vegetation is driven by drought. Our approach is based on the use of remote sensing data and a multi-scalar drought index. Correlation maps between fields of monthly Normalized Difference Vegetation Index (NDVI) and the Standardized Precipitation-Evapotranspiration Index (SPEI) at different time scales (1–24months) were computed for representative months of winter (Feb), spring (May), summer (Aug) and fall (Nov). Results for the period from 1982 to 2006 show large areas highly controlled by drought, although presenting high spatial and seasonal differences, with a maximum influence in August and a minimum in February. The highest correlation values are observed in February for 3months' time scale and in May for 6 and 12months. The higher control of drought on vegetation in February and May is obtained mainly over the drier vegetation communities (Mediterranean Dry and Desertic) at shorter time scales (3 to 9months). Additionally, in February the impact of drought on vegetation is lower for Temperate Oceanic and Continental vegetation types and takes place at longer time scales (18–24). The dependence of drought time-scale response with water balance, as obtained through a simple difference between precipitation and reference evapotranspiration, varies with vegetation communities. During February and November low water balance values correspond to shorter time scales over dry vegetation communities, whereas high water balance values implies longer time scales over Temperate Oceanic and Continental areas. The strong control of drought on vegetation observed for Mediterranean Dry and Desertic vegetation types located over areas with high negative values of water balance emphasizes the need for an early warning drought system covering the entire Mediterranean basin. We are confident that these results will provide a useful tool for drought management plans and play a relevant role in mitigating the impact of drought episodes.

The Evaporative Demand Drought Index. Part I: Linking Drought Evolution to Variations in Evaporative Demand

Abstract Many operational drought indices focus primarily on precipitation and temperature when depicting hydroclimatic anomalies, and this perspective can be augmented by analyses and products that reflect the evaporative dynamics of drought. The linkage between atmospheric evaporative demand E0 and actual evapotranspiration (ET) is leveraged in a new drought index based solely on E0—the Evaporative Demand Drought Index (EDDI). EDDI measures the signal of drought through the response of E0 to surface drying anomalies that result from two distinct land surface–atmosphere interactions: 1) a complementary relationship between E0 and ET that develops under moisture limitations at the land surface, leading to ET declining and increasing E0, as in sustained droughts, and 2) parallel ET and E0 increases arising from increased energy availability that lead to surface moisture limitations, as in flash droughts. To calculate EDDI from E0, a long-term, daily reanalysis of reference ET estimated from the American Society of Civil Engineers (ASCE) standardized reference ET equation using radiation and meteorological variables from the North American Land Data Assimilation System phase 2 (NLDAS-2) is used. EDDI is obtained by deriving empirical probabilities of aggregated E0 depths relative to their climatologic means across a user-specific time period and normalizing these probabilities. Positive EDDI values then indicate drier-than-normal conditions and the potential for drought. EDDI is a physically based, multiscalar drought index that that can serve as an indicator of both flash and sustained droughts, in some hydroclimates offering early warning relative to current operational drought indices. The performance of EDDI is assessed against other commonly used drought metrics across CONUS in Part II.

Spatiotemporal analysis of multiscalar drought characteristics across the Loess Plateau of China

Drought is the most widespread and destructive hazard in arid and semiarid regions, with behaviors that become more complicated under climate change. To provide an overall view of drought conditions across the Loess Plateau of China, two multiscalar drought indices, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), were used to identify the regional spatiotemporal characteristics of drought conditions from 1957 to 2012. Climatic data from 54 meteorological stations across the region were used to calculate the SPI and SPEI time series at 1-, 3-, 6-, 12- and 24-month time scales. Subregions with independent drought characteristics and the corresponding representative meteorological stations were identified by principal component analysis to facilitate regional drought monitoring. A temporal trend of drought severity over a 12-month time scale, as detected by the Mann–Kendall test, was mapped for the entire region. The intensity of the increasing trend of drought severity based on the SPEI was weaker than that based on the SPI. The area with a significant increasing trend of drought severity based on the SPEI was only found in the southwest of the region and was much smaller than that based on the SPI. The temporal behavior of drought frequency from January to December differed over different time scales and levels of drought severity. The regional distributions of the drought frequency were mapped for different months. Generally, the drought frequency spatially decreased from southeast to northwest and was higher in the middle of the winter, late spring and early summer. While the drought-hit area also changed with time, it was generally within the central and northwest areas of the region. Drought behaviors identified by the SPI and SPEI also changed with different time scales. Clear differences were also found among the drought characteristics identified by SPI, SPEI and the self-calibrated Palmer Drought Severity Index. The SPEI is considered as a robust index for regional drought monitoring and analysis under global climate change scenarios because of its multiscalar nature, simple form, low data requirement, and ability to identify the effects of temperature on drought conditions.

Standardized Water Budget Index and Validation in Drought Estimation of Haihe River Basin, North China

The physical-based drought indices such as the self-calibrated Palmer Drought Severity Index (sc-PDSI) with the fixed time scale is inadequate for the multiscalar drought assessment, and the multiscalar drought indices including Standardized Precipitation Index (SPI), Reconnaissance Drought Index (RDI), and Standardized Precipitation Evapotranspiration Index (SPEI) based on the meteorological factors are lack of physical mechanism and cannot depict the actual water budget. To fill this gap, the Standardized Water Budget Index (SWBI) is constructed based on the difference between areal precipitation and actual evapotranspiration (AET), which can describe the actual water budget but also assess the drought at multiple time scales. Then, sc-PDSI was taken as the reference drought index to compare with multiscalar drought indices at different time scale in Haihe River basin. The result shows that SWBI correlates better with sc-PDSI and the RMSE of SWBI is less than other multiscalar drought indices. In addition, all of drought indices show a decreasing trend in Haihe River Basin, possibly due to the decreasing precipitation from 1961 to 2010. The decreasing trends of SWBI were significant and consistent at all the time scales, while the decreasing trends of other multiscalar drought indices are insignificant at time scale less than 3 months.