Figure 1.
Map of the contiguous United States (CONUS). (
a) An example map of the United States Drought Monitor (USDM) on 22 February 2018 [
41]. (
b) Entire sub-watersheds delineated by the Soil and Water Assessment Tool (SWAT) model (3972 watersheds). (
c) Entire grids for the Variable Infiltration Capacity (VIC) model (3275 grids). (
d) Locations of soil moisture observations from the United States Climate Reference Network (USCRN).
Figure 1.
Map of the contiguous United States (CONUS). (
a) An example map of the United States Drought Monitor (USDM) on 22 February 2018 [
41]. (
b) Entire sub-watersheds delineated by the Soil and Water Assessment Tool (SWAT) model (3972 watersheds). (
c) Entire grids for the Variable Infiltration Capacity (VIC) model (3275 grids). (
d) Locations of soil moisture observations from the United States Climate Reference Network (USCRN).
Figure 2.
Spatial maps of drought conditions derived from the USDM, MSDI from SWAT and VIC, and precipitation and temperature anomalies for the retrospective period. For the USDM and MSDI maps, yellow to brown areas represent each category of drought conditions. For the maps of precipitation anomalies, orange or red areas indicate less precipitation than mean values, whereas yellowish green or green areas represent more precipitation than mean values. For the maps of temperature anomalies, yellowish green or green areas indicate lower temperatures than mean values, whereas orange or red areas represent higher temperatures than mean values. (a) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 8 May 2012. (b) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 22 January 2013. (c) Spatial maps of the USDM, precipitation anomalies, and temperature anomalies for 29 April 2014. (d) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 28 April 2015. (e) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 29 November 2016. (f) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 29 November 2016 (18 July 2017).
Figure 2.
Spatial maps of drought conditions derived from the USDM, MSDI from SWAT and VIC, and precipitation and temperature anomalies for the retrospective period. For the USDM and MSDI maps, yellow to brown areas represent each category of drought conditions. For the maps of precipitation anomalies, orange or red areas indicate less precipitation than mean values, whereas yellowish green or green areas represent more precipitation than mean values. For the maps of temperature anomalies, yellowish green or green areas indicate lower temperatures than mean values, whereas orange or red areas represent higher temperatures than mean values. (a) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 8 May 2012. (b) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 22 January 2013. (c) Spatial maps of the USDM, precipitation anomalies, and temperature anomalies for 29 April 2014. (d) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 28 April 2015. (e) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 29 November 2016. (f) Spatial maps of the USDM and MSDI, precipitation anomalies, and temperature anomalies for 29 November 2016 (18 July 2017).
Figure 3.
Comparisons of raw and bias-corrected precipitation and temperature from the CFSv2 dataset. (a) Time series for weekly precipitation from raw (black line) and bias-corrected (green) data for the CONUS. The X-axis represents the forecasting period, and the Y-axis shows weekly precipitation. (b) Spatial map of differences between raw and bias-corrected precipitation during the forecasting period (August 2017 to April 2018). Positive values indicate that higher precipitation was estimated by CFSv2 compared to the mean values of historic observations (1979 to July 2017), and they are symbolized as light blue to blue. Negative values indicate that less precipitation was estimated by CFSv2, and they are symbolized as red. (c) Time-series for weekly mean temperature from raw (black line) and bias-corrected (green) data for the CONUS. The X-axis represents the forecasting period, and the Y-axis shows weekly mean temperature. (d) Spatial map of differences between raw and bias-corrected temperature during the forecasting period (August 2017 to April 2018). Positive values indicate that a higher temperature was estimated by CFSv2 compared to the mean values of historic observations (1979 to July 2017), and they are symbolized as orange to red. Negative values indicate that a lower temperature was estimated by CFSv2, and they are symbolized as yellowish green to green.
Figure 3.
Comparisons of raw and bias-corrected precipitation and temperature from the CFSv2 dataset. (a) Time series for weekly precipitation from raw (black line) and bias-corrected (green) data for the CONUS. The X-axis represents the forecasting period, and the Y-axis shows weekly precipitation. (b) Spatial map of differences between raw and bias-corrected precipitation during the forecasting period (August 2017 to April 2018). Positive values indicate that higher precipitation was estimated by CFSv2 compared to the mean values of historic observations (1979 to July 2017), and they are symbolized as light blue to blue. Negative values indicate that less precipitation was estimated by CFSv2, and they are symbolized as red. (c) Time-series for weekly mean temperature from raw (black line) and bias-corrected (green) data for the CONUS. The X-axis represents the forecasting period, and the Y-axis shows weekly mean temperature. (d) Spatial map of differences between raw and bias-corrected temperature during the forecasting period (August 2017 to April 2018). Positive values indicate that a higher temperature was estimated by CFSv2 compared to the mean values of historic observations (1979 to July 2017), and they are symbolized as orange to red. Negative values indicate that a lower temperature was estimated by CFSv2, and they are symbolized as yellowish green to green.
Figure 4.
Weekly comparisons of drought areas of the United States Drought Monitor (USDM) and drought indices computed from the Variable Infiltration Capacity (VIC) and Soil and Water Assessment Tool (SWAT) models for the period between 2012 and 2017. (a) Weekly drought categories from the USDM. (b) Weekly drought categories from the results of the SWAT model and MSDI. (c) Weekly drought categories from the results of the VIC model and MSDI. (d) Weekly drought categories from the results of the SWAT model and SSI. (e) Weekly drought categories from the results of the VIC model and SSI. (f) Weekly drought categories from the results of the SWAT model and SBI. (g) Weekly drought categories from the results of the VIC model and SBI.
Figure 4.
Weekly comparisons of drought areas of the United States Drought Monitor (USDM) and drought indices computed from the Variable Infiltration Capacity (VIC) and Soil and Water Assessment Tool (SWAT) models for the period between 2012 and 2017. (a) Weekly drought categories from the USDM. (b) Weekly drought categories from the results of the SWAT model and MSDI. (c) Weekly drought categories from the results of the VIC model and MSDI. (d) Weekly drought categories from the results of the SWAT model and SSI. (e) Weekly drought categories from the results of the VIC model and SSI. (f) Weekly drought categories from the results of the SWAT model and SBI. (g) Weekly drought categories from the results of the VIC model and SBI.
Figure 5.
Time-series of mean values of MSDI, SSI, SBI, SPI, and QQ for the CONUS during the retrospective period. Each line indicates the drought index (green: MSDI, orange: SSI, violet: SBI, Blue: SSI), and they are represented by the primary Y-axis (left). Black bars show the QQ values, and they are represented by the secondary Y-axis (right). (a) Results of the SWAT model. (b) Results of the VIC model.
Figure 5.
Time-series of mean values of MSDI, SSI, SBI, SPI, and QQ for the CONUS during the retrospective period. Each line indicates the drought index (green: MSDI, orange: SSI, violet: SBI, Blue: SSI), and they are represented by the primary Y-axis (left). Black bars show the QQ values, and they are represented by the secondary Y-axis (right). (a) Results of the SWAT model. (b) Results of the VIC model.
Figure 6.
Weekly time-series of drought agreement (DA) values for each drought category from the two models. The DA was calculated as the ratio of the intersected area to the total area of the USDM (Intersected area/USDM area). (a) DA values of MSDI from the SWAT model. (b) DA values of MSDI from the VIC model. (c) DA values of SSI from the SWAT model. (d) DA values of SSI from the VIC model. (e) DA values of SBI from the SWAT model. (f) DA values of SBI from the VIC model.
Figure 6.
Weekly time-series of drought agreement (DA) values for each drought category from the two models. The DA was calculated as the ratio of the intersected area to the total area of the USDM (Intersected area/USDM area). (a) DA values of MSDI from the SWAT model. (b) DA values of MSDI from the VIC model. (c) DA values of SSI from the SWAT model. (d) DA values of SSI from the VIC model. (e) DA values of SBI from the SWAT model. (f) DA values of SBI from the VIC model.
Figure 7.
Time series and color maps of soil moisture percentile (first figure), time series of weekly precipitation and temperature (second map), and color map of the USDM (third figure) at the USCRN observation sites for the retrospective period. For the first map, the black line indicates the time-series of soil moisture percentile, and yellow to brown bars represent drought categories. For the second figure, the black line represents the time-series of the weekly mean temperature (°C), and the blue bars indicate the weekly precipitation (mm). For the third figure, the yellow to brown bars represent the drought categories. All boxes represent a period of drought events that includes the D3 or D4 drought category based on soil moisture percentiles (red or brown). (a) Results from the CA1 site. (b) Results from the AZ1 site. (c) Results from the KS1 site. (d) Results from the AL1 site. (e) Results from the VA1 site.
Figure 7.
Time series and color maps of soil moisture percentile (first figure), time series of weekly precipitation and temperature (second map), and color map of the USDM (third figure) at the USCRN observation sites for the retrospective period. For the first map, the black line indicates the time-series of soil moisture percentile, and yellow to brown bars represent drought categories. For the second figure, the black line represents the time-series of the weekly mean temperature (°C), and the blue bars indicate the weekly precipitation (mm). For the third figure, the yellow to brown bars represent the drought categories. All boxes represent a period of drought events that includes the D3 or D4 drought category based on soil moisture percentiles (red or brown). (a) Results from the CA1 site. (b) Results from the AZ1 site. (c) Results from the KS1 site. (d) Results from the AL1 site. (e) Results from the VA1 site.
Figure 8.
Bar charts and attached tables for drought events (all drought categories) based on soil moisture percentile (SMP) and USDM at USCRN observation sites. The Y-axis represents the number of drought events (weeks) and the X-axis indicates each drought category. The red bars represent drought events based on the soil moisture percentile, whereas blue bars indicate drought events based on the USDM. The attached tables shows the total number of drought events. (a) The CA1 site. (b) The AZ1 site. (c) The KS1 site. (d) The AL1 site. (e) The VA1 site.
Figure 8.
Bar charts and attached tables for drought events (all drought categories) based on soil moisture percentile (SMP) and USDM at USCRN observation sites. The Y-axis represents the number of drought events (weeks) and the X-axis indicates each drought category. The red bars represent drought events based on the soil moisture percentile, whereas blue bars indicate drought events based on the USDM. The attached tables shows the total number of drought events. (a) The CA1 site. (b) The AZ1 site. (c) The KS1 site. (d) The AL1 site. (e) The VA1 site.
Figure 9.
Classification of Hydrologic Unit Code 6 (HUC6) watersheds. The X-axis represents the code numbers of HUC6. All of the HUC6 watersheds in the CONUS were classified into twelve groups, and each group was assigned a number from one to twelve. For example, HUC6 watersheds starting with the numbers “12” and “13” were assigned to group number “9”, which is highlighted with the red box and arrow.
Figure 9.
Classification of Hydrologic Unit Code 6 (HUC6) watersheds. The X-axis represents the code numbers of HUC6. All of the HUC6 watersheds in the CONUS were classified into twelve groups, and each group was assigned a number from one to twelve. For example, HUC6 watersheds starting with the numbers “12” and “13” were assigned to group number “9”, which is highlighted with the red box and arrow.
Figure 10.
Results of drought occurrence evaluations for all HUC6 watersheds for the CONUS (317 sub-watersheds): Index of agreement (IA) and index of disagreement (ID) between the USDM and MSDI from the SWAT model for five drought categories during the retrospective period (January 2012 through July 2017). The
Y-axis on the left (primary axis) represents the values of agreement, whereas the
Y-axis on the right (secondary axis) indicates the values of disagreement. The
X-axis shows the HUC6 numbers, which were classified into twelve groups (
Figure 8). (
a) Results of D0. (
b) Results of D1. (
c) Results of D02 (
d) Results of D3. (
e) Results of D4.
Figure 10.
Results of drought occurrence evaluations for all HUC6 watersheds for the CONUS (317 sub-watersheds): Index of agreement (IA) and index of disagreement (ID) between the USDM and MSDI from the SWAT model for five drought categories during the retrospective period (January 2012 through July 2017). The
Y-axis on the left (primary axis) represents the values of agreement, whereas the
Y-axis on the right (secondary axis) indicates the values of disagreement. The
X-axis shows the HUC6 numbers, which were classified into twelve groups (
Figure 8). (
a) Results of D0. (
b) Results of D1. (
c) Results of D02 (
d) Results of D3. (
e) Results of D4.
Figure 11.
Results of drought occurrence evaluations for all HUC6 watersheds for the CONUS (317 sub-watersheds): Index of agreement (IA) and index of disagreement (ID) between the USDM and MSDI from the VIC model for five drought categories during the retrospective period (January 2012 through July 2017). The
Y-axis on the left (primary axis) represents the values of agreement, whereas the
Y-axis on the right (secondary axis) indicates the values of disagreement. The
X-axis shows the HUC6 numbers, which were classified into twelve groups (
Figure 8). (
a) Results of D0. (
b) Results of D1. (
c) Results of D02 (
d) Results of D3. (
e) Results of D4.
Figure 11.
Results of drought occurrence evaluations for all HUC6 watersheds for the CONUS (317 sub-watersheds): Index of agreement (IA) and index of disagreement (ID) between the USDM and MSDI from the VIC model for five drought categories during the retrospective period (January 2012 through July 2017). The
Y-axis on the left (primary axis) represents the values of agreement, whereas the
Y-axis on the right (secondary axis) indicates the values of disagreement. The
X-axis shows the HUC6 numbers, which were classified into twelve groups (
Figure 8). (
a) Results of D0. (
b) Results of D1. (
c) Results of D02 (
d) Results of D3. (
e) Results of D4.
Figure 12.
Spatial maps of drought occurrences (unit: weeks) and annual precipitation (unit: mm) during the retrospective period (291 weeks), as well as a scatter plot that shows a relationship between annual precipitation and the index of disagreement (ID). (a) Spatial map of drought occurrences. Red areas indicate locations where more droughts occurred, whereas green areas represent regions with fewer droughts. (b) Spatial map of annual precipitation. Red areas indicate locations with lower precipitation, whereas blue areas represent regions with higher precipitation. (c) Scatter plot. The Y-axis represents the ID (%) and the X-axis shows the annual precipitation (mm).
Figure 12.
Spatial maps of drought occurrences (unit: weeks) and annual precipitation (unit: mm) during the retrospective period (291 weeks), as well as a scatter plot that shows a relationship between annual precipitation and the index of disagreement (ID). (a) Spatial map of drought occurrences. Red areas indicate locations where more droughts occurred, whereas green areas represent regions with fewer droughts. (b) Spatial map of annual precipitation. Red areas indicate locations with lower precipitation, whereas blue areas represent regions with higher precipitation. (c) Scatter plot. The Y-axis represents the ID (%) and the X-axis shows the annual precipitation (mm).
Figure 13.
Weekly comparisons of drought areas of the USDM and drought indices computed from the VIC and SWAT models for the forecasting period. (a) Weekly drought categories from the USDM. (b) Weekly drought categories from the results of MSDI from the SWAT model. (c) Weekly drought categories from the results of MSDI from the VIC model. (d) Weekly drought categories from the results of SSI from the SWAT model. (e) Weekly drought categories from the results of SSI from the VIC model. (f) Weekly drought categories from the results of SBI from the SWAT model. (g) Weekly drought categories from the results of SBI from the VIC model.
Figure 13.
Weekly comparisons of drought areas of the USDM and drought indices computed from the VIC and SWAT models for the forecasting period. (a) Weekly drought categories from the USDM. (b) Weekly drought categories from the results of MSDI from the SWAT model. (c) Weekly drought categories from the results of MSDI from the VIC model. (d) Weekly drought categories from the results of SSI from the SWAT model. (e) Weekly drought categories from the results of SSI from the VIC model. (f) Weekly drought categories from the results of SBI from the SWAT model. (g) Weekly drought categories from the results of SBI from the VIC model.
Figure 14.
Weekly time series of drought agreement (DA) values of drought indices from the two models for the forecasting period (August 2017 to April 2018). The DA was calculated as a ratio of the intersected area to the total area of USDM (intersected area between USDM and drought indices/USDM). (a) Weekly time-series of DA from the results of MSDI from the SWAT model. (b) Weekly time-series of DA from the results of MSDI from the VIC model. (c) Weekly time-series of DA from the results of SSI from the SWAT model. (d) Weekly time-series of DA from the results of SSI from the VIC model. (e) Weekly time-series of DA from the results of SBI from the SWAT model. (f) Weekly time-series of DA from the results of SBI from the VIC model.
Figure 14.
Weekly time series of drought agreement (DA) values of drought indices from the two models for the forecasting period (August 2017 to April 2018). The DA was calculated as a ratio of the intersected area to the total area of USDM (intersected area between USDM and drought indices/USDM). (a) Weekly time-series of DA from the results of MSDI from the SWAT model. (b) Weekly time-series of DA from the results of MSDI from the VIC model. (c) Weekly time-series of DA from the results of SSI from the SWAT model. (d) Weekly time-series of DA from the results of SSI from the VIC model. (e) Weekly time-series of DA from the results of SBI from the SWAT model. (f) Weekly time-series of DA from the results of SBI from the VIC model.
Figure 15.
Spatial maps and bar charts for a number of grids where the absolute value of differences between monthly precipitation from CPC observations and CFSv2 exceed 20 mm, and monthly mean temperature exceed 1 °C. (a) Spatial maps for a number of grids where the absolute values of differences between monthly precipitation from CPC observation and CFSv2 exceed 20 mm. If a value obtained by subtracting the CPC observation from CFSv2 is less than −20 mm, it is symbolized as red and represents an underestimation compared to CFSv2. However, if the value is more than 20 mm, it is displayed in green and indicates an overestimation compared to CFSv2. Finally, if the value is between −20 and 20 mm, it is symbolized as yellow. (b) Total number of grids where the absolute values of monthly differences exceed 20 mm (c) Spatial maps for a number of grids where the absolute values of differences exceed 1 °C. If a value obtained by subtracting the CPC observation from CFSv2 is less than −1 °C, it is symbolized as red and represents an underestimation compared to CFSv2. However, if the value is more than 1 °C, it is displayed in green and indicates an overestimation compared to CFSv2. Finally, if the value is between −1 °C and 1 °C, it is symbolized as yellow. (d) Total number of grids where the absolute values of monthly differences exceed 1 °C for the forecasting period.
Figure 15.
Spatial maps and bar charts for a number of grids where the absolute value of differences between monthly precipitation from CPC observations and CFSv2 exceed 20 mm, and monthly mean temperature exceed 1 °C. (a) Spatial maps for a number of grids where the absolute values of differences between monthly precipitation from CPC observation and CFSv2 exceed 20 mm. If a value obtained by subtracting the CPC observation from CFSv2 is less than −20 mm, it is symbolized as red and represents an underestimation compared to CFSv2. However, if the value is more than 20 mm, it is displayed in green and indicates an overestimation compared to CFSv2. Finally, if the value is between −20 and 20 mm, it is symbolized as yellow. (b) Total number of grids where the absolute values of monthly differences exceed 20 mm (c) Spatial maps for a number of grids where the absolute values of differences exceed 1 °C. If a value obtained by subtracting the CPC observation from CFSv2 is less than −1 °C, it is symbolized as red and represents an underestimation compared to CFSv2. However, if the value is more than 1 °C, it is displayed in green and indicates an overestimation compared to CFSv2. Finally, if the value is between −1 °C and 1 °C, it is symbolized as yellow. (d) Total number of grids where the absolute values of monthly differences exceed 1 °C for the forecasting period.
Figure 16.
Spatial maps of drought conditions from the USDM and drought indices from the SWAT and VIC models for the forecasting period (August 2017 to April 2018). For the USDM, MSDI, SSI, and SBI maps, yellow to brown areas represent the five categories of drought conditions. (a) USDM and MSDIs for 1 August 2017. (b) USDM and MSDIs for 5 September 2017. (c) USDM and MSDIs for 3 October 2017. (d) USDM and MSDIs for 14 November 2017. (e) USDM and MSDIs for 19 December 2017. (f) USDM and MSDIs for 16 January 2018.
Figure 16.
Spatial maps of drought conditions from the USDM and drought indices from the SWAT and VIC models for the forecasting period (August 2017 to April 2018). For the USDM, MSDI, SSI, and SBI maps, yellow to brown areas represent the five categories of drought conditions. (a) USDM and MSDIs for 1 August 2017. (b) USDM and MSDIs for 5 September 2017. (c) USDM and MSDIs for 3 October 2017. (d) USDM and MSDIs for 14 November 2017. (e) USDM and MSDIs for 19 December 2017. (f) USDM and MSDIs for 16 January 2018.
Table 1.
Descriptions of drought categories associated with the USDM and drought indices derived from the two models used in this study.
Table 1.
Descriptions of drought categories associated with the USDM and drought indices derived from the two models used in this study.
USDM Category | Description | Range of Drought Indices |
---|
D0 | Abnormally dry | −0.50 to −0.79 |
D1 | Moderate drought | −0.80 to −1.29 |
D2 | Severe drought | −1.30 to −1.59 |
D3 | Extreme drought | −1.60 to −1.99 |
D4 | Exceptional drought | −2.0 or less |
Table 2.
Mean drought agreement (DA) values for three drought indices from the SWAT and VIC models during the retrospective period (January 2012 to July 2017) (unit: %).
Table 2.
Mean drought agreement (DA) values for three drought indices from the SWAT and VIC models during the retrospective period (January 2012 to July 2017) (unit: %).
Model | Drought Indices | D0 | D1 | D2 | D3 | D4 |
---|
SWAT-DA | MSDI | 63 | 45 | 35 | 21 | 9 |
SSI | 65 | 48 | 37 | 23 | 9 |
SBI | 55 | 38 | 28 | 16 | 7 |
VIC-DA | MSDI | 66 | 49 | 41 | 26 | 12 |
SSI | 67 | 54 | 47 | 30 | 15 |
SBI | 65 | 51 | 44 | 28 | 14 |
Table 3.
Annual precipitation and six years’ mean precipitation for the CONUS during last 36 years (unit: mm).
Table 3.
Annual precipitation and six years’ mean precipitation for the CONUS during last 36 years (unit: mm).
Years | Annual Precipitation | Six Years Mean (1982–1983) | Years | Annual Precipitation | Six Years Mean (1988–1993) | Years | Annual Precipitation | Six Years Mean (1994–1999) |
1982 | 848 | 795 | 1988 | 653 | 770 | 1994 | 771 | 800 |
1983 | 869 | 1989 | 730 | 1995 | 826 |
1984 | 784 | 1990 | 812 | 1996 | 858 |
1985 | 750 | 1991 | 816 | 1997 | 798 |
1986 | 793 | 1992 | 792 | 1998 | 847 |
1987 | 729 | 1993 | 819 | 1999 | 699 |
Years | Annual Precipitation | Six Years Mean (2000–2005) | Years | Annual Precipitation | Six Years Mean (2006–2011) | Years | Annual Precipitation | Six Years Mean (1982–1983) |
2000 | 686 | 726 | 2006 | 727 | 765 | 2012 | 671 | 754 |
2001 | 699 | 2007 | 734 | 2013 | 746 |
2002 | 699 | 2008 | 789 | 2014 | 750 |
2003 | 735 | 2009 | 808 | 2015 | 825 |
2004 | 810 | 2010 | 789 | 2016 | 771 |
2005 | 730 | 2011 | 741 | 2017 | 759 |
Table 4.
Some properties of United States Climate Reference Network (USCRN) sites.
Table 4.
Some properties of United States Climate Reference Network (USCRN) sites.
Site Name | USCRN Code | Longitude | Latitude | Observation Period |
---|
CA1 | CA_Fallbrook_5_NE | −123.07 | 38.32 | September 2011—Current |
AZ1 | AZ_Yuma_27_ENE | −112.34 | 35.76 | August 2009—Current |
KS1 | KS_Manhattan_6_SSW | −96.61 | 39.1 | August 2009—Current |
AL1 | AL_Selma_13_WNW | −85.96 | 34.29 | June 2009—Current |
VA1 | VA_Cape_Charles_5_ENE | −75.93 | 37.29 | June 2011—Current |
Table 5.
Mean values of index of agreement (IA) values for drought indices from the SWAT and VIC models (unit: %).
Table 5.
Mean values of index of agreement (IA) values for drought indices from the SWAT and VIC models (unit: %).
Model | Drought Indices | D0 | D1 | D2 | D3 | D4 |
---|
SWAT | MSDI | 70 | 53 | 43 | 28 | 12 |
SSI | 71 | 56 | 46 | 29 | 12 |
SBI | 64 | 48 | 37 | 21 | 7 |
VIC | MSDI | 72 | 56 | 48 | 32 | 13 |
SSI | 74 | 60 | 52 | 35 | 17 |
SBI | 71 | 56 | 47 | 28 | 12 |
Table 6.
Mean DA values for drought indices and categories from the two models for the forecasting period between August 2017 and January 2018 (unit: %). Higher values indicate that the drought indices captured drought conditions better compared to USDM categories.
Table 6.
Mean DA values for drought indices and categories from the two models for the forecasting period between August 2017 and January 2018 (unit: %). Higher values indicate that the drought indices captured drought conditions better compared to USDM categories.
Model | Drought Indices | D0 | D1 | D2 | D3 | D4 |
---|
SWAT | MSDI | 64 | 60 | 47 | 34 | 25 |
SSI | 42 | 35 | 16 | 2 | 1 |
SBI | 25 | 13 | 6 | 2 | 0 |
VIC | MSDI | 62 | 61 | 48 | 35 | 25 |
SSI | 35 | 27 | 9 | 2 | 0 |
SBI | 29 | 22 | 9 | 2 | 0 |