IHOP-2002 Data Archive and Development of Composite Data Sets

Steven F. Williams, Scot M. Loehrer, Linda E. Cully, Darren R. Gallant, Janine

Goldstein, and Don Stott

UCAR/Joint Office for Science SupportIHOP-2002 Spring Science Workshop

Boulder, CO March 2003

http://www.joss.ucar.edu/ihop/dm/

IHOP-2002 Data Policy and Protocol

http://www.joss.ucar.edu/ihop/dm/photo.html

IHOP-2002 DATA BASE STATUS(as of 24 March 2003)

• 196 of 254 Data sets (77%) have been submitted or linked. 183 are available on-line (13 in progress)

• Field Catalog (w/reports and preliminary products) is on-line

• Data submission instructions and guidelines are available on-line

• For details see: http://www.joss.ucar.edu/ihop/dm/

Composites: What and Why

A composite dataset is a collection (over some time period and region) of similar data (e.g. surface met) from a variety of sources, put into a common format, and passed through a uniform quality control.

Why does UCAR/JOSS develop composites?

- Provides data in a uniform format with QC.

- Allows determination of network/site problems.

- Useful for model applications.

- Prevents duplication of effort.

Composite Data Sets To Be Developed by UCAR/JOSS for IHOP-2002

• Surface Meteorological - 1 min, 5 min, and Hourly

• Precipitation - 15 min, Hourly, and Daily

• Soundings - High Resolution and

5 hPa

1-min Surface Meteorological Data Composite (65 stations)

ASOS (41)

ARM SMOS (14)

ABLE AWS (5)

NCAR Supp. (5)

Oklahoma Mesonet (115)

NCAR ISS/ISFF (10)

West Texas Mesonet (34)

1-min sites (65)

5-min Surface Meteorological Data Composite (224 stations)

Hourly Surface Meteorological Data Composite (743 stations)

CoAgMet (*) (23)

AWOS (*) (110)

RAWS (+) (10)

SCAN (o) (6)

GWMD (*) (18)

Ameriflux (+) (3)

HPCN (o) (72)

Texas ET (o) (19)

KVII-TV (+) (4)

MADIS (o) (246)

NMSU (*) (7)

5-min sites (o) (225)

15-minute Precipitation Composite

NCDC Coop (429)

5-min surface (224)

Hourly Precipitation Composite

NCDC Coop (509)

NCEP hourly (1155)

Hourly Met (743)

Daily Precipitation Composite

NCDC Coop (1581)

Hourly Met (743)

NCEP Daily (1611)

GENERAL DATASET PROCESSING LIFE CYCLE

Contact SRC Agency to Acquire Data and Metadata

Wait for SRC Agency Data/Metadata Preparation

Examine Data & Metadata for Consistency and Completeness

Acquire Data and Metadata OR Create “Best” Metadata

Develop New Software or Modify Existing Software

Acquire Computer System Space and Time

Process Data and Metadata then Check

Form Composite with Like Datasets

Perform QC and Final Data Checks. Generate Statistics

Create EBUFR format data & DOCS for CODIAC

Load Data and Metadata onto CODIAC

ACTION

Prepare ASCii format data & docs for CD-Roms

Prepare, manufacture, & distribute CD-Roms

Add stn info to final list

Incomplete?

ProcessingProblems?

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Incomplete?

Incomplete?

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• Phone, email, paperwork, $, meetings, procurement arrangements. (Days to months)

• (Minutes to months)

• Auto retrieval, FTP, online requests, etc. (minutes to days)

• Verify AOI, TOI, Format; spot check values, visual inspection or limited processing (Minutes to days)

• Format change, new parameters manual “cleanup”, etc. (Days to months)

• Purchase hardware, configuration management, etc. (Minutes to days)

• Put into common format, run data checkers “check gross limits” (Days to months)

• HQC for SFC, Gross limits for precip, Composite level and value checkers, limited statistics (% G, B, D by network, stn, parameter for SFC). (days to months)

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QC of Surface Meteorological Data

• Parameters: Calculated Sea Level Pressure, Sea Level Pressure, Temperature, Dew Point, Wind Speed, Wind Direction

• Expected value derived from objective analysis method adapted from Cressman (1959) and Barnes (1964) using 300km Radius of Influence.

Σθiwi

Σwi

i

i

θe = Expected Value

θi = Observation at site i

wi = Weight factor for site i where wi = 1/di

di = Distance between site i and QC site

θe =

QC of Surface Meteorological Data • Deviation between actual and expected values subjected

to dynamically determined limits. Values compared at like solar times.

Limits are sensitive to diurnal and intra-seasonal variations and dependent upon spatial and temporal continuity.

• Additional consistency checks, visual quality assurance, and gross limit checks are typically also applied.

• Precipitation gross limit checked based on frequency.• Data are never changed, only flagged.

α = Normalization Factor (predetermined)

σ = Standard Deviation (computed over previous 30 days for each time; 15 obs minimum)

θa - θe ασ

What Can Lead to Surface Data Being Flagged?

• Instrument failure, bias, drift, random errors• Incorrect latitude, longitude, or elevation• Differences in siting or height of instruments• Misidentified units, dates, or stations• Terrain impacts• Data problems at surrounding stations• Unique meteorological phenomena

Obvious Problems Detected

Subtle Problems Detected

Embedded Accumulative Precipitation

High Resolution and 5 hPa Radiosonde Composites

Fixed Sites: Mobile Sites:

NWS (14) ARM (5) ISS (1) Falcon Drops (86) Learjet (330) NCAR GLASS (146) NSSL CLASS

(80)

UCAR/JOSS Atmospheric Sounding Processing Procedures

Observing System Output e.g. NWS Micro-ART

Convert to JOSS Quality-control Calculate Derived

Format (ASCII) Parameters

Vertical Consistency Checks

QC Flags

Gross Limit Checks

Automated Checks QC Flags

e.g., u, v, dz/dt

Visual Examination

Error Files

High-resolution and/or Interpolated Vertical Composite e.g., 5 hPa

Inventory, Archive, and Develop Metadata

Data and Metadata Available Online

Wind Oscillations

• Wind oscillations at low elevation angles (approaching limiting angles) due in part to questionable angles.

Original Algorithm

Adjusted Algorithm

Summary

• The High Resolution and 5 hPa Radiosonde Composites have been completed and are available: http://www.joss.ucar.edu/ihop/dm

• Surface Meteorological (1-min, 5-min, and hourly) and Precipitation (15-min, hourly, and daily) Composites currently being developed. Planned completion Fall 2003.