ENSURING THE CONTINUITY OF LONG-TERM HIGH-QUALITY UTLS WATER VAPOR MEASUREMENT RECORDS WITH NOAA FROST POINT HYGROMETERS THE PROPOSED WORK WILL ENSURE THAT LONG-TERM HIGH-QUALITY VERTICAL PROFILE MEASUREMENTS OF WATER VAPOR IN THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE (UTLS) BY BALLOON-BORNE NOAA FROST POINT HYGROMETERS (FPHS) WILL CONTINUE AT THREE MONITORING SITES: BOULDER COLORADO (40 N) HILO HAWAII (20 N) AND LAUDER NEW ZEALAND (45 S). THE NOAA FPH RECORD OVER BOULDER COLORADO IS THE LONGEST OBSERVATIONAL DATA SET IN EXISTENCE FOR UTLS WATER VAPOR (36.2 YR). SIMILAR BUT SHORTER FPH SOUNDING PROGRAMS AT LAUDER NEW ZEALAND (12.8 YR) AND HILO HAWAII (5.5 YR) PROVIDE CRITICALLY IMPORTANT RECORDS OF UTLS WATER VAPOR MIXING RATIOS IN THE SOUTHERN MIDDLE LATITUDES AND NORTHERN TROPICS RESPECTIVELY. THE FPH MEASUREMENT PROGRAMS ARE IN JEOPARDY BECAUSE FINANCIAL SUPPORT FROM NOAA S CLIMATE PROGRAM OFFICE HAS CONTINUED TO DECREASE. SUPPORTING FUNDS WILL HELP TO CONTINUE AND IMPROVE THE EXISTING FPH SOUNDING PROGRAMS THAT ARE BENEFICIAL TO NASA S SPACE-BORNE UTLS WATER VAPOR MEASUREMENTS IN SEVERAL WAYS. FIRST THE IN SITU MEASUREMENTS CREATE A BASIS FOR DETECTING AND CORRECTING ANY BIASES AND/OR DRIFTS IN SATELLITE INSTRUMENTS LIKE THE AURA MICROWAVE LIMB SOUNDER (MLS) AND THE SOON-TO-BE-DEPLOYED STRATOSPHERIC AEROSOL AND GAS EXPERIMENT (SAGE-III) ON THE INTERNATIONAL SPACE STATION (ISS). TRENDS IN UPPER ATMOSPHERIC WATER VAPOR ARE OFTEN SMALL AND THEREFORE DIFFICULT TO DETECT WITHOUT THE EXCELLENT LONG-TERM ACCURACY OF FPH MEASUREMENTS. SECOND MONTHLY FPH SOUNDINGS WOULD ALSO HELP TO FILL ANY TEMPORAL GAP THAT MAY OCCUR IN THE AVAILABILITY OF UTLS WATER VAPOR MEASUREMENTS BY SPACE-BORN SENSORS. THIRD THE FPH SOUNDINGS AT BOULDER HILO AND LAUDER ARE NOW VITAL TO TWO INTERNATIONAL OBSERVATIONAL NETWORKS FOCUSED ON THE DETECTION OF TRENDS IN ATMOSPHERIC SPECIES AND ESSENTIAL CLIMATE VARIABLES: THE NETWORK FOR THE DETECTION OF ATMOSPHERIC COMPOSITION CHANGE (NDACC) AND THE GLOBAL CLIMATE OBSERVING SYSTEM (GCOS) REFERENCE UPPER AIR NETWORK (GRUAN). SITE OPERATIONS FOR BOTH NETWORKS ARE SELF-FUNDED HENCE THERE IS A FUNDAMENTAL NEED FOR A NUMBER OF CORE SITES WITH SUSTAINABLE MONITORING PROGRAMS SUCH AS BOULDER HILO AND LAUDER.