Center for Satellite Applications and Research (STAR) Review 09 – 11 March 2010

GOES Solar Radiation Products in Support of Renewable Energy

Istvan Laszlo1(GOVERNMENT PRINCIPAL INVESTIGATOR), Hongqing Liu2, Andrew Heidinger1, Mitch Goldberg1

1NOAA/NESDIS/STAR/SMCD, 2DPSGSRequirements: •Expand and enhance advanced technology monitoring and observing systems to

provide accurate, up-to-date information.•Develop and apply new technologies, methods, and models to increase the

capabilities, efficiencies, and accuracy of transportation-related products and services.

Science: How does the solar radiation available at the surface change as a function of atmospheric and surface conditions?

Benefit: The renewable energy industry will have surface solar radiation products that•benefit siting of future solar farms, •help integration of solar energy into the national and regional electrical grid

systems, and•increase confidence in resource estimation for future planning.

Science Challenges: Calibration of past and current GOES visible measurements should be improved to increase accuracy of insolation products. Separation of atmospheric and surface effects, and estimation of surface solar radiation over snow remain challenging.

Next Steps: Improve retrievals over snow; Implement new aerosol climatology and improve retrieval of direct beam irradiance; Re-process historic GOES data.

Transition Path: Update processing system for new satellite; disseminate data via the internet and archive at NCDC.

The Retrieval Algorithm

Surface Solar Radiation Products at STAR

The solar energy business sector requires high quality solar radiation data (total irradiance and direct beam irradiance) that provide national and regional coverage, especially in regions with high potential for solar energy (SE).

Surface solar radiation estimated from measurements made by instruments on geostationary platforms can provide the data needed as these satellites make frequent observations of the same location during the course of a day. Several such products are generated or planned at STAR.

Evaluation of GOES Surface Solar Radiation

Example of GSIP-fd Results

Characteristics of GOES Surface Solar Radiation Products

Current Future

Product GSIP-CONUS GSIP-fd GOES-R/ ABI

Domain CONUS Northern Hemisphere (NH)

Full Disk (FD)

CONUS (C)

Full Disk (FD)

Mesoscale (M)

Spatial Resolution ~56 km

(0.5x0.5 degrees)

~14 km (4 km)

(1/8x1/8 degrees)

C: 25 km (2km)

FD: 50 km (2km)

M: 5 km

Temporal Res. instantaneous instantaneous instantaneous

Refresh rate 1 hour 1 hour (NH); 3 hours (FD 1 hour (15 minutes)

Latency 50 minutes 50 minutes 54 minutes

Variables provided •all-sky surface global downward SW flux•all-sky surface global upward SW flux•all-sky surface diffuse downward SW flux•all-sky surface global downward visible•all-sky surface diffuse downward PAR•clear-sky surface global downward SW flux•clear-sky surface global upward SW flux

•all-sky surface global downward SW flux•all-sky surface global upward SW flux•all-sky surface global downward visible•clear-sky surface global downward SW flux•clear-sky surface global upward SW flux

•all-sky surface global downward SW flux•all-sky surface global absorbed (net) SW flux•(all-sky surface direct downward SW flux)

Evaluation with historic data. Bias (top) and root-mean-square (bottom) differences of hourly (left) and monthly (right) GSIP-fd and surface fluxes for Feb-Dec 2001. Land sites: BON, FPK, GWN, PSU. Ocean sites; COVE, TAO1, TAO2.

Acquire GOES Imager files

Generate Clear Composite

GOES Imager AREA Files

GFS data

Acquire and remap IMS snow data

IMS snow data

GSIP-v2retrieve cloud

properties, retrieve SW flux,retrieve LW flux

Pre-processing Main processing

ReformattedGFS data

netCDF format conversion

Image generation

netCDF output

Images

GSIPValidation

System

AREA files for previous 28 days

28-day clear

composite file

RemappedIMS snow

data

Output data file:HDF and binary,

Gridded values ofcloud properties,

SW fluxes,visible flux at

surface,LW fluxes,

skin temperature

Acquire and reformat GFS

data

Input Data– GOES Area channel files

• Satellites: GOES East & GOES West• Domains: Full Disk & Northern Hemisphere

Extended• For GOES-11, Channels 1-5• For GOES-12+, Channels 1-4,6

– NCEP Global Forecast System• 12-hour forecast, 0.5 degree grid

– Interactive Multisensor Snow and Ice Mapping System (IMS) data

Intermediate Data– Clear Composite (28-day darkest-pixel

composite of 0.64 micron channel)Output Data

– GSIP output products (38) for GENHEM, GEDISK, GWNHEM, GWDISK domains

– All output products in a single file– Output formats: HDF, netCDF, binary

Ancillary Data– Coast mask, land mask, landcover type,

elevation– RTM coefficients– Algorithm LUTs

Users of GOES Surface Solar Radiation Product

Examples of VIS channel 1 reflectance and inputs to the insolation algorithm for Aug 11, 2004, 17:45 UTC

VIS reflectance (%) Composite clear reflectance (%) Clear and partly clear reflectance (%) Cloudy and partly cloudy reflectance (%)

Cloud fraction Water vapor (cm) Ozone (cm)Dominant cloud type0:clear, 1:partly cloudy,

2:liquid water, 3:supercooled liquid,4:thick ice (convective), 5:thin ice

Illustration of retrieval of transmittance from TOA albedo (reflectance) for the geometry and atmospheric condition shown (no surface effects). The clear-sky/cloudy-sky transmittance is ~0.69/0.28 corresponding to the TOA albedo of 0.1/0.5.

0.0 0.2 0.4 0.6 0.80.0

0.2

0.4

0.6

0.8

0: 0.6

H20: 2.0 g cm-2

O3: 0.3 atm-cm

Aerosol: CONT-I (: 0.0-1.5)Cloud: water (: 0-80)Cloud top: 5.5 kmCloud bottom: 2kmSurface albedo: 0

Shortwave Transmittance vs. TOA Reflectance

Cloudy sky Clear sky

Tra

nsm

ittance

Reflectance

Principle of Surface Radiation Retrieval

Example of surface SW irradiance retrieved in the GSIP-fd system for the extended Northern Hemisphere for January 6, 2010. Frequent observations may permit forecast of insolation for short time periods into the future.

Primary source of ground data is the NOAA Surface Radiation Budget Network (SURFRAD).

Solar Energy specific ProductsAverage insolation (Amount of solar radiation incident on the surface of the Earth)

Midday insolation (Average insolation available within 1.5 hours of Local Solar Noon)

Clear sky insolation (Average insolation during clear sky days)

Clear sky days (Number of clear sky days (cloud amount < 10%))

Diffuse radiation on horizontal surface (Amount of solar radiation incident on the surface of the earth under all-sky conditions with direct radiation from the Sun's beam blocked )

Direct normal radiation (Amount of solar radiation at the Earth's surface on a flat surface perpendicular to the Sun's beam with surrounding sky radiation blocked)

Insolation at hourly intervals (Amount of solar radiation incident on the surface of the Earth during one hour)

Insolation clearness index (Fraction of insolation at the top of the atmosphere which reaches the surface of the Earth)

Insolation normalized clearness index (Zenith angle-independent expression of the insolation clearness index)

Clear sky insolation clearness index (Fraction of insolation at the top of the atmosphere which reaches the surface of the earth during clear sky days)

Minimum available insolation as % of average values over consecutive-day period (Insolation based on minimum consecutive-day insolation over various numbers of days within the month)