Variability of TTL water vapor

A filtered CFH climatology andMLS water vapor for Ticosonde/Costa

Rica

Rennie Selkirk, NASA GSFC/GESTARMark Schoeberl, STC

ATTREX Science Team MeetingNCAR – 24 October 2013

Sonde processing

• Objectives: – Highlight the large seasonal variability in TTL WV– Need to remove CFH noise in at scale of ~100 m

• Approach:– Low-pass filter – with attention to data gaps– Apply to all variables– Calculate seasonal climo on data from 2005-2011– Will soon add 2012 and 2013

Temperatures at Costa Rica

CFH Water Vaporwith previous season

RH ice

Both seasons show rapid fall off of mean RHice profile at mean coldpoint (dashed lines)

WV tape recorder at Costa Rica(seasonal time averages)

Season Min T (“coldpoint tropopause

”)

WV at Tmin

1st WV tape recorder min

(“hygropause”)

1st WV tape recorder max

Upper WV tape

recorder min

DJF -82.6° C (17.4 km)

2.7 ppmv 2.5 ppmv (17.9 km)

4.4 ppmv (20.5 km)

3.4 ppmv (23 km)

MAM -81.3° C (17.2 km)

3.3 ppmv 2.9 ppmv (17.4 km)

4.5 ppmv (22 km)

n/a

JJA -76.7° C (16.1 km)

6.5 ppmv 3.5 ppmv (19.7 km)

4.9 ppmv (24.1 km)

n/a

SON -79.3° C (16.7 km)

4.2 ppmv 4.2 ppmv (16.8 km)

5.3 ppmv (17.8 km)

3.5 ppmv (21.6 km)

Water Vapor vs Ozone

DJF JJA

MLS water vapor intecomparisons

• Long-term average data – MLS WV, version 3, interpolated via MERRA to San Jose

and in potential temperature– Can be used to compare to CFH seasonal climatology

• MLS RDFs:– Back-trajectory-based product– Synthetic high-vertical resolution water vapor (and

ozone) profiles– Use to infer day-to-day variability at a sounding

location

Sondes vs. MLS v.3

Winter composite

(36 sondes)

Summer composite

(60 sondes)

MLS RDF @ SJOSummer 2007

MLS RDFs vs CFH

****

* *

*MLS RDF

profile(previous

slide)

Summary

• Strong seasonal cycle of water vapor in UTLS at Costa Rica Low-pass filtering of CFH data– Tape recorder prominent

• Low-pass filtering reduces instrumental noise– But may reduce frequency of high RH in TTL too strongly

• Seasonal average fields consistent with MLS, v.3• MLS RDFs promising technique for reproducing

vertical structure seen in sondes