Atmospheres Panel Report to the Payload Panel

This report is the outgrowth of the Atmospheres Panel meeting held in September 1991. The Panel was asked to either endorse or reject the CEES and IPCC research priorities for global change and to indicate which EOS candidate instruments, in the Panel's opinion, made the most significant contributions to answering the scientific questions associated with the CEES and IPCC priorities. After some discussion, the Panel endorsed the CEES and IPPC priorities as presented by Dr. Watson at the Seattle IWG. However, the Panel remained very concerned about significant weakness in the proposed stratospheric instrument package associated with hydroxyl and halogen measurements. This concern is expressed in our recommendation list below. This report is divided into five sections. The first section is a summary of recommendations of the Panel. The summary contains the list of primary instruments needed to answer the major science questions which the Panel has identified. The four sections following detail our recommendations. They are: (1) Clouds, Radiation and Precipitation, (2) Tropospheric Chemistry, (3) Stratospheric Chemistry and Dynamics and (4) Data Assimilation. While the separation of these issues may seem artificial, these four categories represent the cores of merging disciplines within the atmospheric sciences. In order to expose the reasoning behind instrument prioritization, the Panel reiterated the key science questions and then discussed the approach used to answer those questions. From the approach, measurement needs and instrument priorities follow logically. Additional subsections briefly discuss constraints on the remote measurements (if any) and other relevant measurement programs (if any); major recommendations follow. EOS instruments matching the data requirements for a given science objective are divided into three categories: Primary, Ancillary and Contributing. The order of listing within the category does not indicate prioritization; it is random. A Primary Instrument is one directly relevant to the core science questions. A Contributing Instrument is one whose measurement would add to the overall pool of information in a positive way, but loss of data from that instrument would not cripple the science objectives as would loss of data from a Primary Instrument. Ancillary Instruments occupy the gray area in between. The Panel recognizes the measurements made by Ancillary Instruments as contributing significantly to some science objectives, but not all Panel members felt that an ancillary instrument was core to a given science objective.