Some Experiences and Recent Advances in Surface Radiation Measurements Ellsworth G. Dutton NOAA ESRL Global Monitoring Division Boulder, Colo

GATE -1974, USCG Dallas Kirby Hanson’s Met & Radiation Boom

CMDL Baseline Observatories Trinidad Head, CA 40 N Barrow, Alaska 71 deg. N American Samoa 14 deg. S. Mauna Loa, Hawaii 19 deg. N South Pole – 90 S 1956 to present - solar transmission (Mauna Loa only) 1975 to present - total downwelling solar irrad 1976 to present – wideband direct solar – AOD ~1985 to present – downwelling thermal IR ~1985 to present – upwelling irradiances 1995 to present – WCRP BSRN participation

Surface Radiation Budget Components, time averaging LW  LW  SW  SW  Erie Tower NOAA/BSRN GMD

WMO IOC Regions Oceanic Tropics Desert Polar Coastal Rain forest Agricultural Prairie E.G. Dutton, 14APR06 Features Site scientists 18+ countries Stand. Specs. Long-term Central archive Ref. Std. Devlp. GRP review GCOS Archiving Provisional Goal: To acquire the highest possible quality, climati- cally-diverse, surface-based radiation measurements for climate & remote sen. applications Data Applications GCM comparisons Satellite prod. validation Regional climatologies Radiation budget apps. Radiation model testing Measurements Direct & diffuse solar* Downward infrared * Upwelling irrad. PAR & UV Aerosol optical depth Surface meteorology* Upper air met. Sky imagery, cloud height * all sites 1992 – 2006+

NOAA / BSRN Instrument close-ups

Surface-based broadband radiation measurement issues addressed by BSRN Spatial representativeness of data Extent of climatic regimes sampled Calibration references, SW diffuse & LW Component sum vs. global SW Thermal errors in thermopile sensors Effects and benefits of artificial ventilation UV, PAR, albedo, aerosol O.D. Specifications and Operations Manual

BSRN (and the world) needs more in situ, representative, oceanic surface radiation measurements BSRN is an international cooperative project of the World Climate Research Program and GEWEX and as such has NO central funding, only volunteers generally working as their country’s radiation experts and representatives to WMO/WCRP are involved – these folks are called BSRN Site Scientists with their own national or whatever funding. BSRN requires adherence to its specifications. WARNING:

BSRN has a new (2004) Oceanic Working Group Issues – platforms, measurement accuracy (available and required), moving sites, instrument orientation, obstructions, sea spray+, lack of upper air soundings… Assess the required accuracy needed in interesting very data-poor regions to contribute to satellite and climate model projects Revisit BSRN specifications and consider drafting an oceanic version Inventory candidate platforms Recruit potential participants – encourage improvements Evaluate of impact on stated requirement for long-time series and other complications Ken Rutledge NASA/Langley chair (Chesapeake Light House SS) Contact me if interested --

188 pp Step 1.Assess current accuracy and that required to contribute to atmospheric research. Step 2. Figure out how to get there. The BSRN approach

Philipona and Marty Improving Ground-based Radiation Meas. Calibration Standards Wm -2 Michalsky et al 2004, 2006 Step 3. Get there.

Candidate Reference, ASR PYRGEOMETERS IPASRC-I Oklahoma ARM/SGP

Philipona et al., 2001/Marty et al., 2003 IR Radiometer Intercomparisons Difference Relative to Proposed Ref. Meas. (Wm -2 ) Observations Models BSRN-ARM/CMDL 1999 Mid-West US, W m Arctic – Barrow, W m -2

Michalsky et al., 2005 Clear-sky surface radiative closure, diffuse and direct Average of 30 cases on 13 days S. Kato C. GueymardC. Gueymard

Avg. (337) BSRN (344) Circa 2005 GCM models global means M. Wild 2001& 2005 Over last 6 years climate models approach BSRN downwelling IR results BSRN (344 W m -2 ) Model Avg. (329) Circa 1999 GCM models (global means)

Satellite Results: Downward Surface SW Flux (Wm -2 ) Downward Surface LW Flux (Wm -2 ) GEWEX SRB Paul Stackhouse, NASA/Langley Long-term Annual Averages

Figure 13. Scatter plots for all the available monthly mean surface fluxes from BSRN and corresponding values from ISCCP-FD: (a) S9s and (b) L9s in Wm!2. Statistics from the plot are given in Table 7a. Y. Zhang, W. B. Rossow, A. A. Lacis, V. Oinas, M M. Mishchenko, accepted JGR, 2004 ISCCP model BSRN LW, monthly avg SW, monthly avg BSRN Comparison to a new satellite product

SRB Validation: Reanalysis, CERES Surface-only fluxes (time averaged) BSRN sites: Bermuda, Billings, Florinapolis, Goodwin Creek, Kwajalein, Manus, Tateno

Summary Surface-based surface solar and infrared radiation measurements are of considerable value today. BSRN has pursued improving the accuracy and confidence of surface irradiance obs. Work is ongoing to establish recognized and lasting radiation reference standards. An IPCC Radiative Flux Assessment is being prepared. While BSRN was original intended for fixed-site, ground- based observations, a substantial need for open-ocean obs has emerged and BSRN is attempting to address that need. Potential BSRN-like shipboard radiation measurements include: downwelling solar and longwave irradiances, direct and diffuse solar, Aerosol optical depth, cloud imagery, meteorology, PRT SST…

The End

NOAA Station data x-correlated with NASA / ISCCP annual averages, total surface solar Units are X-Corr. Coef. / S. E. ▲ ▲ ▲ SMO ▲ ▲ BLD E. Dutton et al., 2006

BSRN Operational Measurement Quality Compiled by Paul Stackhouse NASA/SRB