Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

Marine ARM GPCI Investigations of Clouds (MAGIC): Infrared Seasurface Temperature Autonomous Radiometer (ISAR)

1 September 2012 - 30 September 2013

Lead Scientist: R. Reynolds

Observatory: amf, mag

Sea surface temperature (SST) is one of the most appropriate and important climate parameters: a widespread increase is an indicator of global warming and modifications of the geographical distribution of SST are an extremely sensitive indicator of climate change. There is high demand for accurate, reliable, high spatial and temporal resolution SST measurements for the parameterisation of ocean-atmosphere heat, momentum and gas (SST is therefore critical to understanding the processes controlling the global carbon dioxide budget) fluxes, for detailed diagnostic and process orientated studies to better understand the behavior of the climate system, as model boundary conditions, for assimilation into climate models and, for the rigorous validation of climate model output. These demands require complete confidence in the content, interpretation, accuracy, reliability and continuity of observational SST data; criteria that can only be fulfilled by the successful implementation of an on-going data product validation strategy.

ISAR mounted on the SPIRIT bridge port rail. The GPS (left antenna) provides location data and the Iridium SBD (right antenna) is used for ship-to-shore data telemetry every half hour. The AMF2 IRT radiometers are located to the left of the ISAR.

The Infrared Sea surface Temperature Autonomous Radiometer (ISAR) system has been developed to collect high quality in situ observations of the radiative sea surface (skin) temperature, SSST, that can be used to validate the SSST observations made by several satellite systems (ENVSAT, MODIS, AQUA). The ISAR is carefully calibrated to NIST standards and one of this IOP is to ensure that the satellite retrievals of SSST have characterized uncertainties and that the validation procedure provides traceability to NIST standards and therefore can be legitimately considered a Climate Data Record. Traceability to NIST standards is retained by careful maintenance of the laboratory calibration equipment at Univ. of Miami and University of Washington, and periodic recalibration of the reference thermometers.

The ISAR is a compact (570 x 220 mm) precision, self-calibrating, infrared radiometer capable of measuring in situ SSST accurate to ±0.1 C rmse that has been developed in collaboration with scientists at the National Oceanography Centre, Southampton (NOCS) UK, Brookhaven National Laboratory (BNL) USA, and European Commission, Italy. The ISAR uses two precision calibration black body (BB) cavities to maintain the radiance calibration of a solid-state infrared detector having a spectral window of 9.6-11.5μm. All ISAR target views are made using a single route optical path via a protective scan drum arrangement that may be programmed to any target view to positioned over a range of 160°. In this way, views of the atmosphere can be made at regular intervals providing the necessary measurements required to correct sea view radiance data for sky radiance reflection due to the non-unity value of sea water emissivity.

The ISAR system on SPIRIT has an external GPS and a pitch and roll sensor. These provide important information for estimating the precise SSST. In addition it incorporates an Iridium short-burst data (SBD) modem so SSST measurements can be transmitted to shore on a regular (half hour) schedule. During the cruises, SSST data are given quality assurance by comparisons with SST maps and with co-located data buoys.

A trackline showing SSST for MAGIC Leg04. Day points are shown as year day from 292 to 306. The typical temperature field from 16 C to 27 C is apparent. The cold tongue of water near the California coast is indicative of the prevalent coastal upwelling there.

Co-Investigators

Peter Minnett

Timeline

  • Parent Campaign
  • Sibling Campaign

Campaign Data Sets

IOP Participant Data Source Name Final Data
R. Reynolds Infrared Seasurface Skin Temperature Autonomous Radiometer Order Data

MAG Data Sources

Name Full Name Browse Data
AOS Aerosol Observing System Browse Data
AOSMET Meteorological Measurements associated with the Aerosol Observing System Browse Data
ASSIST Atmospheric Sounder Spectrometer for Infrared Spectral Technology Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CEIL Ceilometer Browse Data
CEILPBLHT Boundary-layer height data with CEIL Browse Data
CEILSHIPCOR Ceilometer Corrected for Ship Motion Browse Data
CPC Condensation Particle Counter Browse Data
HSRL High Spectral Resolution Lidar Browse Data
HSRLSHIPCOR HSRL Corrected for Ship Motion Browse Data
HTDMA Humidified Tandem Differential Mobility Analyzer Browse Data
INTERPSONDE Interpolated Sonde Browse Data
IRT Infrared Thermometer Browse Data
KAZR Ka ARM Zenith Radar Browse Data
KAZRSHIPCOR KAZR Ship Motion Correction Browse Data
MARINEMET Marine Surface Meteorological Instrumentation Browse Data
MPL Micropulse Lidar Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MPLPOLFSSHIPCOR MPL Corrected for Ship Motion Browse Data
MWACR Marine W-Band (95 GHz) ARM Cloud Radar Browse Data
MWACRSHIPCOR MWACR Ship Motion Correction Browse Data
MWR Microwave Radiometer Browse Data
MWR3C Microwave Radiometer, 3 Channel Browse Data
MWRRET MWR Retrievals Browse Data
NAV Navigational Location and Attitude Browse Data
NAVBE Navigational Location and Attitude Best Estimate Browse Data
NEPHELOMETER Nephelometer Browse Data
OZONE Ozone Monitor Browse Data
PBLHT Planetary Boundary Layer Height Browse Data
PRP Portable Radiation Package Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
RWP Radar Wind Profiler Browse Data
SASZE Shortwave Array Spectroradiometer-Zenith Browse Data
SONDE Balloon-Borne Sounding System Browse Data
SONDEGRID Gridded Sonde VAP Product Browse Data
S-TABLE Stabilized Platform Browse Data
TSI Total Sky Imager Browse Data
UHSAS Ultra-High Sensitivity Aerosol Spectrometer Browse Data