RDW_Climate/Moisture_Difference_ZScore

View In: ArcGIS JavaScript ArcGIS Online Map Viewer ArcGIS Earth

Service Description: The Moisture Deficit and Surplus map uses moisture difference z-score (MDZ) datasets developed by scientists Frank Koch, John Coulston, and William Smith of the Forest Service Southern Research Station to represent drought and moisture surplus across the contiguous United States. A z-score is a statistical method for assessing how different a value is from the mean. Mean moisture values over 1-year windows were derived from monthly historical precipitation and temperature data from PRISM, between 1900 and 2023, and compared against a 1900-2017 baseline. The greater the z-value, the larger the departure from average conditions, indicating larger moisture deficits (droughts) or surpluses. Thus, the dark orange areas on the map indicate a 1-year window with extreme drought, relative to the average conditions over the past century. For further reading on the methodology used to build these maps, see the publication here: https://www.fs.usda.gov/treesearch/pubs/43361

Name: RDW_Climate/Moisture_Difference_ZScore_1yr

Description: Detailed technical methods for this analysis are available here: https://www.fs.usda.gov/treesearch/pubs/43361. This is derived from monthly PRISM temperature and precipitation data, located here: ftp://prism.nacse.org/monthly/. Monthly temperature data are used to calculate potential evapotranspiration (PET) using the Thornthwaite PET equation. Monthly precipitation and PET data are then used to calculate a moisture index (MI) for each month within a 1-year time window. The mean moisture index (MMI) across the months of the target window is compared to an appropriate long-term normal, in this case the average of the MMI for all windows between 1900 and 2017. Then, a moisture difference z-score (MDZ) is calculated from the MMI for the window of interest. This is done by subtracting the 1900-2017 normal MMI from the MMI for a given year, and then dividing by the standard deviation over the baseline period. Equations for calculating modified moisture index are adopted from Willmott, C.J. and Feddema, J.J. 1992. A more rational climatic moisture index. Professional Geographer 44(1): 84-87. The z-score values were then reclassified using the classification scheme below: z-score less than -2 -- extremely dry compared to normal conditions z-score -2 to -1.5 -- severely dry compared to normal conditions z-score -1.5 to -1 -- moderately dry compared to normal conditions z-score -1 to -0.5 - mildly dry compared to normal conditions z-score -0.5 to 0.5 -- near normal conditions z-score 0.5 to 1 -- mildly wet compared to normal conditions z-score 1 to 1.5 -- moderately wet compared to normal conditions z-score 1.5 to 2 -- severely wet compared to normal conditions z-score more than 2 -- extremely wet compared to normal conditions

Single Fused Map Cache: false

Extent:

Initial Extent:

Full Extent:

Time Info:

[1900/01/01 00:00:00 UTC, 2023/01/01 00:00:00 UTC]

Pixel Size X: 4638.312116423505

Pixel Size Y: 4638.312116423505

Band Count: 1

Pixel Type: S16

RasterFunction Infos: {"rasterFunctionInfos": [ { "name": "MDZ_color_table", "description": "A raster function template.", "help": "" }, { "name": "None", "description": "Make a Raster or Raster Dataset into a Function Raster Dataset.", "help": "" } ]}

Mensuration Capabilities: Basic

Inspection Capabilities:

Has Histograms: false

Has Colormap: false

Has Multi Dimensions : false

Rendering Rule:

Min Scale: 0

Max Scale: 0

Resampling: false

Copyright Text: USDA Forest Service Office of Sustainability and Climate; Southern Research Station

Service Data Type: esriImageServiceDataTypeThematic

Min Values: N/A

Max Values: N/A

Mean Values: N/A

Standard Deviation Values: N/A

Object ID Field: OBJECTID

Fields:

OBJECTID ( type: esriFieldTypeOID, alias: OBJECTID )
Shape ( type: esriFieldTypeGeometry, alias: Shape )
Name ( type: esriFieldTypeString, alias: Name, length: 200 )
MinPS ( type: esriFieldTypeDouble, alias: MinPS )
MaxPS ( type: esriFieldTypeDouble, alias: MaxPS )
LowPS ( type: esriFieldTypeDouble, alias: LowPS )
HighPS ( type: esriFieldTypeDouble, alias: HighPS )
Category ( type: esriFieldTypeInteger, alias: Category , Coded Values: [0: Unknown] , [1: Primary] , [2: Overview] , ...6 more... )
Tag ( type: esriFieldTypeString, alias: Tag, length: 100 )
GroupName ( type: esriFieldTypeString, alias: GroupName, length: 100 )
ProductName ( type: esriFieldTypeString, alias: ProductName, length: 100 )
CenterX ( type: esriFieldTypeDouble, alias: CenterX )
CenterY ( type: esriFieldTypeDouble, alias: CenterY )
ZOrder ( type: esriFieldTypeInteger, alias: ZOrder )
Shape_Length ( type: esriFieldTypeDouble, alias: Shape_Length )
Shape_Area ( type: esriFieldTypeDouble, alias: Shape_Area )
Year ( type: esriFieldTypeSmallInteger, alias: Year )

Default Mosaic Method: Northwest

Allowed Mosaic Methods: NorthWest,Center,LockRaster,ByAttribute,Nadir,Viewpoint,Seamline,None

SortField:

SortValue: null

Mosaic Operator: First

Default Compression Quality: 75

Default Resampling Method: Nearest

Max Record Count: 1000

Max Image Height: 50000

Max Image Width: 50000

Max Download Image Count: 20

Max Mosaic Image Count: 20

Allow Raster Function: true

Allow Copy: true

Allow Analysis: true

Allow Compute TiePoints: false

Supports Statistics: true

Supports Advanced Queries: true

Use StandardizedQueries: true

Raster Type Infos:

Has Raster Attribute Table: false

Edit Fields Info: null

Ownership Based AccessControl For Rasters: null

Child Resources: Info Statistics Key Properties Legend Raster Function Infos

Supported Operations: Export Image Query Identify Measure Compute Histograms Compute Statistics Histograms Get Samples Compute Class Statistics Query GPS Info Find Images Image to Map Map to Image Measure from Image Image to Map Multiray Query Boundary Compute Pixel Location Compute Angles Validate Project

RDW_Climate/Moisture_Difference_ZScore_1yr (ImageServer)