Connecting Jason-3 to the Long-term Sea Level Record: Results from Harvest and Regional Campaigns

Bruce Haines (Jet Propulsion Laboratory, California Institute of Technology, United States)

CoAuthors

Shailen Desai (Jet Propulsion Laboratory, California Institute of Technology, United States); Adam Dodge (Colorado Center for Astrodynamics Research, University of Colorado, Boulder, United States); Bob Leben (Colorado Center for Astrodynamics Research, University of Colorado, Boulder, United States); Dallas Masters (Colorado Center for Astrodynamics Research, University of Colorado, Boulder, United States); Chirstian Meinig (NOAA Pacific Marine Environmental Laboratory, Seattle, United States); Steve Nerem (Colorado Center for Astrodynamics Research, University of Colorado, Boulder, United States); Rashmi Shah (Jet Propulsion Laboratory, California Institute of Technology, United States); Scott Stalin (NOAA Pacific Marine Environmental Laboratory, Seattle, United States)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Regional and Global CAL/VAL for Assembling a Climate Data Record

Presentation type: Type Oral

We describe the latest satellite radar altimeter calibration/validation (CALVAL) results from data collected at the Harvest offshore platform. Located 10 km off the coast of central California near Point Conception, Harvest has hosted a dedicated CALVAL facility for 25 years, dating to the launch of TOPEX/POSEIDON in August 1992. Harvest is directly in the path of the 10-d repeat ground track for the primary reference (Jason-class) altimeter missions, enabling the development of a continuous 25-year calibration record based on direct (overhead) passes of the platform.

Based on data collected during overflights of the latest (Jason-3) mission, we estimate the sea-surface height (SSH) bias is 0 ± 12 mm (one standard error with N= 29). In contrast, results for Jason-2 continue to yield a slight positive bias: +20 ± 2 mm (N=249; accounting for systematic errors, however, the bias is only slightly significant). Jason-2 has since been shifted to an interleaved repeat orbit which no longer passes over the platform. In terms of characterizing SSH stability using the Harvest data, only the Jason-1 and -2 missions have long enough time series at this time to support monitoring of drift at the 1 mm/yr level or better. Neither the Jason-1 nor Jason-2 SSH drift estimates are statistically distinguishable from zero. We update these results using information from new overflights.

We also report new campaign results from neighboring Jason ground tracks. These campaigns include: 1) a three-month deployment (May–Sept. 2016) of a precise GPS buoy at a Jason-2/3 crossover location (Daisy Bank) off the coast of Oregon; 2) a provisional tide gauge occupation (beginning June 2017) on Catalina Island along the ascending track (No. 119) adjacent to and south of Harvest; 3) a two-month deployment (July–Sept. 2017) of a precise GPS buoy in Monterey Bay along the ascending track (No. 221) adjacent to and north of Harvest. Early results from these campaigns testify to the potential of similar techniques for expanding the calibration footprint of Harvest in order to support other altimeter missions such as SWOT.
 

Oral presentation show times:

RoomStart DateEnd Date
Symphony Ballroom IV Wed, Oct 25 2017,09:00 Wed, Oct 25 2017,09:15
Bruce Haines
Jet Propulsion Laboratory, California Institute of Technology
United States
Bruce.J.Haines@jpl.nasa.gov