Monitoring the JMR Wet Path Delays

Shailen Desai

Bruce Haines

Victor Zlotnicki

November 18, 2003 Jason-1 Science Working Team MeetingCal/Val Splinter Session

SD/BH/VZ - 2

JMR versus ECMWF

• +3-4 mm step between cycles 29-32

• -5 mm step at cycle 2 caused by change to ECMWF model

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Differences of Wet Path Delay Corrections, (JMR-ECMWF) (mm)

Jason-1 Repeat Cycle

Smoothed

November 18, 2003 Jason-1 Science Working Team MeetingCal/Val Splinter Session

SD/BH/VZ - 3

Comparisons to GPS observations

• Similar +4-5 mm step in JMR path delays found in comparisons to GPS.

• ECMWF model relatively stable in comparison.

• Smaller scatter after cycle 36 when ECMWF model modified.– Smaller scatter in (JMR-

ECMWF) differences (from 1.5 to 1.25 cm).

November 18, 2003 Jason-1 Science Working Team MeetingCal/Val Splinter Session

SD/BH/VZ - 4

Comparison to SSM/I and TMI

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0 100 200 300 400 500 600Daily Average of Differences of Wet PD Corrections, (JMR-SSMI) (mm)

Days Since Jan 1, 2002

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0 100 200 300 400 500 600Daily Average of Differences of Wet

PD Corrections, (JMR-TMI) (mm)

Days Since Jan 1, 2002

November 18, 2003 Jason-1 Science Working Team MeetingCal/Val Splinter Session

SD/BH/VZ - 5

Attitude Dependence

• Attitude dependence of JMR wet PD correction may have returned after cycle 33.

– Verification by other methods pending (e.g. SSM/I and TMI).

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Pass Averages of Wet PD

Differences, (ECMWF-JMR) (mm)

Passes Since Start of Cycle 48

Fixed to SineSine to Fixed

November 18, 2003 Jason-1 Science Working Team MeetingCal/Val Splinter Session

SD/BH/VZ - 6

Geographically Correlated Error?

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Cycles 29-59

Cycles 2-27

• Comparisons to SSM/I and TMI suggest possible geographically correlated errors in JMR wet PD.• Color scale is from -9 to +9 mm.

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