Improved software has been developed at NCEIdroughtgov for calculating Palmer drought indices There are slight differences in results when compared to the 1980s vintage software currently used usually in transition periods as drought intensifies and ameliorates ID: 1025170
Download Presentation The PPT/PDF document "Deke Arndt has a Question" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Deke Arndt has a QuestionImproved software has been developed at NCEI/drought.gov for calculating Palmer drought indicesThere are slight differences in results when compared to the 1980s vintage software currently used, usually in transition periods as drought intensifies and amelioratesWe believe that the improved software is correct but needs more testingOnce we are confident, we recommend adopting the new softwareDo you concur? Please see Deke if you have comments / reservations1
2. Efficacy of Drought Indices Derived from In Situ Soil Moisture ObservationsRonald D. LeeperMichael A. PaleckiBryan Petersen
3. Soil Moisture Index ObjectivesSoil moisture is one of the most rapidly growing in situ measurements in the U.S., and yet there few hydrological indices focused on actual soil moisture observations. Our aim is to develop an in situ based soil moisture index that will be:Able to provide relative measures of soil Dryness and Wetness at a locationAvailable in near-real timeWidely adoptable by other networks and monitoring platforms (i.e. satellite) The index will be evaluated against USDM conditions to understand how the index responds to evolving drought conditions, from drought worsening to improving conditions.
4. Standardized Soil Moisture DatasetThe soil moisture index will be based on USCRN’s hourly standardized soil moisture dataset, and compared against USDM conditions.Leeper, R. D., J. E. Bell, and M. A. Palecki, 2019. A description and evaluation of U.S. Climate Reference Network Standardized Soil Moisture Dataset. Journal Applied Meteorology and Climatology, 58, 1417 - 1428. http://dx.dio.org/10.1175/JAMC-D-18-0269.1
5. Soil Moisture IndexAll standardized measures were aggregated to temporally align with USDM.Variables of interestWeekly averaged anomaly and percentile (1 to 8 weeks)Standardized soil moisture anomaly trends (4-8 weeks)Percent of 30th & 70th percentile threshold exceedance (1 to 8 weeks)Depths of interest:5, 10, and 20 cm levelsSoil Moisture Index (SMID) = Term1D + Term2D Where D is depth
6. Histograms revealed that averaged percentile and anomaly provided more robust separation between drought and no drought and status change.HistogramsSoil moisture trends may only be relevant during drought or onset
7. In addition to USDM status, drought events were defined for each station.A minimum D1 status requirementAt least six weeks of D0 status or less between successive eventsNoneD2D4D1-6-4-2-1-3-5135642Drought EventPredroughtPost DroughtUSDM Based Drought Events
8. Drought Events
9. Drought Events Continued
10. Multi-Measure Index
11. SummarySoil moisture measures aligned well with evolving USDM conditions from diverse locations across the U.S.Histograms revealed that anomalies and percentiles were able to partially distinguish drought from non-drought conditions.Multi-measure or multi-depth indices may improve these resultsSoil moisture based drought index can provide insight with regard to drought onset and drought intensification.
12. Up For DiscussionThe USDM integrates multiple time scale considerations and expert input to describe drought status, which can vary greatly from a measure focused on one aspect of the hydrological cycle.Measures of vegetation health (NDVI, vegDRI, station photos) may provide the basis for more direct assessment of soil moisture based drought indices.Are there any specific requirements you might have for further development of drought indices?