Project Grant 80NSSC18K0116

THIS PROPOSAL SEEKS TO EXTEND LONG-TERM MICROWAVE MIDDLE ATMOSPHERIC MEASUREMENTS OF OZONE CHLORINE MONOXIDE AND WATER VAPOR WHICH HAVE BEEN SUPPORTED BY NASA AND HAVE BEEN PART OF THE NETWORK FOR ATMOSPHERIC COMPOSITION CHANGE (NDACC) SINCE THE EARLY 1990 S. THE MEASUREMENT DATABASE CONSISTS OF O3 AND H2O MEASUREMENTS FROM MAUNA LOA HAWAII AND LAUDER NEW ZEALAND; CLO MEASUREMENTS FROM MAUNA KEA HAWAII AND SCOTT BASE ANTARCTICA; AND H2O MEASUREMENTS FROM TABLE MOUNTAIN CALIFORNIA. ALL THREE OF THESE SPECIES PLAY AN IMPORTANT ROLE IN THE CLIMATE SYSTEM. OZONE MEASUREMENTS ARE ESSENTIAL TO MONITOR THE BEGINNING OF ITS RECOVERY AND CLO MEASUREMENTS ARE NEEDED TO INTERPRET THIS PROCESS. WATER VAPOR IS THE RESERVOIR OF ODD HYDROGEN IN THE MIDDLE ATMOSPHERE AND IS THEREFORE ALSO IMPORTANT TO OZONE CHEMISTRY. IT HAS ALSO BEEN SUGGESTED THAT VARIATIONS IN STRATOSPHERIC H2O HAVE HAD A SIGNIFICANT IMPACT ON DECADAL-SCALE GLOBAL SURFACE CLIMATE CHANGE. TO ILLUSTRATE THE SCIENTIFIC VALUE OF THESE MEASUREMENTS WE DISCUSS SEVERAL STUDIES CONDUCTED DURING THE 2013-2017 PROPOSAL CYCLE WHICH MAKE USE OF THESE LONG-TERM DATASETS. THESE INCLUDED LONG-TERM TREND STUDIES OF CLO OVER MAUNA KEA [CONNOR ET AL. 2013] STUDIES OF H2O OVER BOTH MAUNA LOA AND TABLE MOUNTAIN [NEDOLUHA ET AL. 2013A; NEDOLUHA ET AL. 2013B] A STUDY OF DIURNAL O3 VARIATIONS OVER MAUNA LOA [PARRISH ET AL. 2014] AND STUDIES OF THE EFFECTS OF CHANGING ATMOSPHERIC DYNAMICS ON O3 [NEDOLUHA ET AL. 2015A; NEDOLUHA ET AL. 2015B]. IN ADDITION A MANUSCRIPT RELATED TO LONG-TERM TRENDS IN CLO OVER SCOTT BASE HAS BEEN SUBMITTED [NEDOLUHA ET AL. 2016]. FINALLY THE DATA HAS AND IS BEING USED IN A NUMBER OF STUDIES LED BY OTHER AUTHORS. THE MOST IMPORTANT GOAL OF THIS WORK IS TO MAINTAIN STABLE MEASUREMENTS IN ORDER TO ENSURE THE ACCURATE DETECTION OF LONG-TERM CHANGE. IN ORDER TO ENSURE CONTINUED STABLE OPERATION INSTRUMENTS NEED TO BE UPDATED. THIS WILL MAKE IT POSSIBLE TO MAINTAIN THE INSTRUMENTS WITH CURRENTLY AVAILABLE TECHNOLOGY AND WILL REDUCE THE LONG-TERM MAINTENANCE REQUIREMENTS SO THAT WE CAN KEEP THEM OPERATING WITH A SINGLE FIELD ENGINEER AND SOME ON-SITE SUPPORT. THE H2O INSTRUMENTS UNDERWENT SIGNIFICANT UPDATES DURING THE 2009-2013 PROPOSAL CYCLE AND HAVE REQUIRED MINIMAL TECHNICAL ATTENTION DURING THE 2013-2017 PROPOSAL CYCLE. DURING THE 2013-2017 PROPOSAL CYCLE WE HAVE UNDERTAKEN MAJOR UPGRADES OF THE O3 INSTRUMENT AT MAUNA LOA AND A CLO INSTRUMENT WHICH BECAUSE OF ANTI-TELESCOPE PROTESTS HAD TO BE MOVED FROM MAUNA KEA TO MAUNA LOA. WHILE THE O3 INSTRUMENT HAS NOT YET UNDERGONE A FULL VALIDATION STUDY SEVERAL MONTHS OF RETRIEVALS AND COMPARISONS WITH AURA MLS SUGGEST THAT IT IS OPERATING SATISFACTORILY. THERE ARE SEVERAL MAJOR TECHNICAL TASKS WHICH WE PLAN TO ACCOMPLISH IN THE 2017-2021 TIMEFRAME. WE PLAN TO REPLACE THE CRYOGENICALLY OPERATING O3 RECEIVERS AT MAUNA LOA AND LAUDER WITH ROOM TEMPERATURE VERSIONS JUST AS HAS BEEN DONE FOR THE H2O SYSTEMS. WHILE THIS MAY RESULT IN SOME LOSS OF SIGNAL-TO-NOISE AND WILL RESULT IN AN INTERRUPTION OF MEASUREMENTS AT LAUDER ARE NOT IN GENERAL SIGNALTO- NOISE LIMITED AND IT WILL PUT THEM ON A MORE SUSTAINABLE LONG-TERM FOOTING. WE HAVE RETRIEVED CLO WITH THE NEW INSTRUMENT NOW ON MAUNA LOA AND THE INSTRUMENT APPEARS TO BE OPERATING VERY WELL BUT IT IS NOT YET CLEAR WHETHER CONDITIONS AT THIS SITE WHICH ARE SOMEWHAT POORER THAN ON MAUNA KEA WILL ALLOW US TO MAKE SUFFICIENT TRENDQUALITY CLO MEASUREMENTS. WE ARE CURRENTLY INVESTIGATING OPTIONS TO RETURN TO MAUNA KEA IN THE EVENT THAT CONDITIONS AT MAUNA LOA ARE FOUND TO BE NOT FULLY SATISFACTORY. THE CHALLENGE OF REPLACING THE AGING SCOTT BASE CLO INSTRUMENT IS THE MOST DAUNTING. AS A FIRST STEP TO THIS WE HAVE NEARLY FINISHED DEVELOPING A NEW CHLOE INSTRUMENT IN THE LAB AT NRL. THIS INSTRUMENT WILL FIRST BE DEPLOYED TO HAWAII AND AFTER COMPARISONS BETWEEN THE TWO CLO INSTRUMENTS IN HAWAII WE WILL MOVE ONE TO SCOTT BASE.