Rolling Review of Requirements Application area: Atmospheric chemistry

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1 Application area: Atmospheric chemistry The Rolling Requirements Review (RRR) Process The process consists of four stages: (i) a review of users' requirements for observations, within an area of application covered by WMO programmes; (ii) a review of the observing capabilities of existing and planned observing systems; (iii) a "Critical Review" of the extent to which the capabilities (ii) meet the requirements (i); and (iv) a "Statement of Guidance" based on (iii). In atmospheric chemistry area 4 challenges are identified: air quality, climate change, oxidation capacity and stratospheric ozone depletion

2 Atmospheric chemistry: Statement of Guidance The aim of the Statement of Guidance, together with the output of the Critical Review, is: To inform WMO Members on the extent to which their requirements are met by present systems, will be met by planned systems, or would be met by proposed systems. It also provides the means whereby Members, through the Technical Commissions, can check that their requirements have been correctly interpreted and can update them if necessary, as part of the Rolling Requirements Review process. To provide resource materials useful to WMO Members for dialogue with observing system agencies regarding whether existing systems should be continued or modified or discontinued, whether new systems should be planned and implemented, and whether research and development is needed to meet unfulfilled aspects of the user requirements.

3 Atmospheric chemistry: User requirements The user requirements are not system dependent, they are intended to be technology free. No consideration is given to what type of measurement characteristics, observing platforms, or data processing systems are necessary (or even possible) to meet them. The requirements are aimed at the time frame. The goal is a maximum requirement. It is an ideal value above which further improvement of the observation would not cause any significant improvement in performance for the application in question. The cost of improving the observations beyond the goal would not be matched by a corresponding benefit. The Goals are likely to evolve as applications progress and develop a capacity to make use of better observations. The hreshold is the minimum requirement that has to be met to ensure that data are useful. Below this minimum, the benefit derived does not compensate for the additional cost involved in using the observation. Threshold requirements for any given observing system cannot be stated in an absolute sense; assumptions have to be made concerning which other observing systems are likely to be available. Within the range between threshold and goal requirements, the observations become progressively more useful. The breakthrough is an intermediate level between hreshold and goal which, if achieved, would result in a significant improvement for the targeted application. The breakthrough level may be considered as an optimum from a cost benefit point of view, when planning or designing observing systems.

4 Atmospheric chemistry: Observing system capabilities Initially, attention has focused on the capabilities of the GOS space based subsystem. At present, the performance of elements of the GOS surface based subsystem have also been characterized in a similar manner.

5 Atmospheric chemistry: the Critical Review The presentation must be concise and attractive, and understandable to senior managers and decision makers, whilst retaining sufficient detail to represent adequately the full range of observation requirements and observing system capabilities; GAW Report 140

6 Atmospheric chemistry: current status Taking account of several realistic financial and logistic constraints, the chemical species and parameters to be included in IGACO were selected using the following criteria: a. the chemical species or variable plays an important role in one or more of the four key atmospheric chemistry issues, identified in IGACO, and there is added value in its incorporation in an integrated global observation system; b. it is now possible, or likely to be possible, to measure the atmospheric constituent or parameter globally and on a long-term basis so as to achieve a synergism between satellite, ground-based and aircraft observations, and model assimilation systems.

7 Atmospheric chemistry: current status Requirements are copied from IGACO report There is no throughout Critical Review in IGACO report IGACO is biased to ozone related species Not all of these IGACO species are GAW focal areas Review is urgently needed Some GAW variables are not in IGACO list ozone (O 3 ) carbon monoxide (CO) chlorine monoxide (CIO) CFC-12 (CF 2 CI2) methane (CH 4 ) sulfur dioxide (SO 2 ) nitrogen monoxide (NO) water vapour (H 2 O) nitrogen dioxide (NO 2 ) hydrogen chloride (HCI) HCFC-22 (CHCIF 3 ) formaldehyde (HCHO) nitric acid (HNO 3 ) methyl bromide (CH 3 Br) carbon dioxide (CO 2 ) bromine oxide (BrO) nitrous oxide (N 2 O) chlorine nitrate (CIONO 2 ) volatile organic compounds (VOC) chlorine dioxide (OCIO) halons (e.g. CF 3 Br) J(NO 2 ) and J(O 1 D) (UV radiation at specific wavelengths in the troposphere).

8 Atmospheric chemistry: current status Some of the key recommendations of IGACO regarding evolution of the GOS for atmospheric chemistry include: (a) long term validation of satellite observations: in order to ensure the accuracy and consistency of satellite measurements, sustained quality assurance measures, over the entire lifetime of satellite sensors, are essential. (b) Validation of vertical profile data from satellite observations: a set of high performance scientific instruments using ground, aircraft and balloon platforms, possibly operated on campaign basis, must be maintained to provide the crucial validation data. (c) Comparability: the ability to merge observations of different types must be ensured by insisting that appropriate routine calibration and comparison activities linking diverse measurements together are part of an individual measurement. (d) Development of comprehensive chemical modules in weather and climate models with appropriate data assimilation should be an integral part.

9 TABLE 2 ATMOSPHERIC SPECIES TO BE MEASURED BY AN INTEGRATED GLOBAL OBSERVING SYSTEM - A Atmospheric region Requirement Unit H 2 O O 3 CH 4 CO 2 CO NO 2 BrO ClO HCl CFC-12 1 x km 5/25 <5/50 10/50 10/500 10/250 10/2 50 Lower z km 0.1/1 0.5/2 2/3 0.5/2 0.5/2 0.5/3 1 Troposphere precision % 1/10 3/20 1/5 0.2/1 1/20 10/3 10 2* trueness % 2/15 5/20 2/10 1/2 2/25 15/4 15 4* delay (1)/(2) (1)/(2) (1)/(2) (1)/(2) (1)/(2) (1) (2) 2 x km 20/100 10/100 50/250 50/500 10/250 30/250 Upper Troposphere z km 0.5/2 0.5/2 2/4 1/2 1/4 0.5/3 precision % 2/20 3/20 1/10 0.5/2 1/20 10/30 N/R trueness % 2/20 5/30 2/20 1/2 2/25 15/40 N/R delay (1)/(2) (1)/(2) (1)/(2) (1)/(2) (1)/(2) (1) 3 x km 50/200 50/100 50/ /500 50/250 30/ Lower Stratosphere z km 1/3 0.5/3 2/4 1/4 2/5 1/4 1 1 precision % 5/20 3/15 2/20 1/2 5/15 10/ trueness % 5/20 5/20 5/30 1/2 10/25 15/ delay (1)/(2) (1)/(2) (1)/(2) (2)/(3) (2)/(3) (1) (2) (2) 4 x km 50/200 50/100 50/ / /500 30/ Upper stratosphere, z km 2/5 0.5/3 2/4 2/4 3/10 1/4 1 1 Mesosphere precision % 5/20 3/15 2/4 1/2 10/20 10/ trueness % 5/20 5/20 5/30 1/2 10/25 15/ delay (1)/(2) (1)/(2) (1)/(2) (2)/(3) (2)/(3) (1)/(2) (2) (2) 5 x km 50/200 10/50 10/250 50/500 10/250 30/ Total column precision % 0.5/2 1/5 1/5 0.5/1 1/10 1/ trueness % 1/3 2/5 2/10 1/2 2/20 2/20 10 delay (1)/(2) (1)/(2) (1)/(2) (2)/(3) (1)/(2) (1) (2) 6 Tropospheric x km 10/200 10/50 10/50 10/500 10/250 10/ Column precision % 0.5/2 5/15 1/5 0.5/1 2/20 1/10 4 trueness % 1/3 5/15 2/10 1/2 5/25 2/10 10 delay (1)/(2) (1)/(2) (1)/(2) (1)/(2) (1)/(2) (1)

10 delay (1) (1)/(2) TABLE 3 ATMOSPHERIC SPECIES TO BE MEASURED BY AN INTEGRATED GLOBAL OBSERVING SYSTEM - B Atmospheric region Requirement Uni t NO HNO 3 C 2 H 6 CH 3 Br Halons HCFC-2 2 ClON O 2 HCHO SO 2 UVA JNO 2 UVB JO 3 1 x km 10/250 10/ * 1 1 Lower Troposphere z km 0.5/3 1/3? precision % 10/30 10/ * 15* 2* /10* trueness % 15/40 15/ * 20* 4* * delay (1) (1)/(2) (1) (1) 2 x km 30/250 10/ N/R N/R N/R /500 Upper Troposphere z km 0.5/3 1/ ** precision % 10/30 10/30 10 N/R N/R N/R trueness % 15/40 15/40 15 N/R N/R N/R delay (1) (1)/(2) (1) (1) 3 x km 30/250 50/ N/A Lower stratosphere z km 1/4 1/4 5 5 precision % 10/30 10/ trueness % 15/40 15/ delay (1) (1)/(2) 4 x km 30/250 50/250 Upper stratosphere, z km 1/40.5 1/4 mesosphere precision % 10/30 10/30 trueness % 15/40 15/40 delay (1)/(2) (2)/(3) 5 Total x km 30/250 30/ column precision % 1/10 1/ trueness % 2/20 2/20 15 delay (1) (2)/(3) (2) 6 Tropospheric x km 10/250 10/ column precision % 1/101 1/ trueness % 2/20 2/

11 How to communicate RRR outcome to WMO members The sixth Session of the CBS Expert Team on the Evolution of global observing systems (ET-EGOS) will be held in Geneva, Switzerland, from 14 to 17 June Contributions are expected no later than 13 May Atmospheric Chemistry (updated by Len Barrie in July 2004). Len Barrie and John Eyre had discussed on how to handle the URs and SoG for Atmospheric Chemistry in future. A mechanism similar to that used for Climate Monitoring has been proposed. The Team agreed that: 2. (i) the GCOS model should be used (i.e. the adequacy report being seen as a SoG) to address Atmospheric Chemistry and avoid duplication of work; 3. (ii) the WMO database needs to be updated with Atmospheric chemistry requirements and observing systems capabilities; and 4. (iii) a dedicated study should be made for the impact of the space based component of the GOS (virtual constellations).

12 How to communicate RRR outcome to WMO members 8) Atmospheric Chemistry Review target application areas for operational Atmospheric Composition (AC) monitoring as articulated by GAW, EU GMES GAS, NAS/ NRC decadal survey, CEOS ACC etc Review the available gap analyses that have been carried out by the space agencies targeting application areas of relevance to AC monitoring e.g. NAS/NRC s decadal survey, CEOS ACC Gap Analysis, EUMETSAT user consultation processes, ESA commissioned studies, including the Dossier on the Space-Based Component of the GOS,etc. Compare to any needs expressed by GAW R.Munro 28 Feb 2010 R.Munro 28 Feb Review Actions identified in the GCOS Implementation Plan of relevance to AC monitoring and determine whether there is a need for ET-EGOS to respond Cross-check available user requirements for spacebased operational AC monitoring measurements for consistency, including the Dossier on the Space-Based Component of the GOS. R.Munro 28 Feb 2010 R.Munro 30 Apr 2010

13 ATMOSPHERIC COMPOSITION ISSUES Strategy Basis for the strategy is the GAW Strategic Plan. It is an elaboration of the actions required to implement the IGACO vision. It includes targets for development and integration of surface, aircraft and satellite observations: It specifically identifies actions required to develop and maintain ground-based and aircraft observation networks, It recognises increasing availability of satellite observations and outlines a plan for furthering interaction with the satellite community and satellite developers. This strategy includes all elements necessary for implementation of GAW as a contribution to the WIGOS. These elements comprise organisational components (e.g NMHSs, SAGs, central facilities), observing systems, quality assurance, data management, integration and application of observations. As a result, the EGOS-IP need refer to the GAW Strategic Plan. An area where additional action is recommended is the coordination of satellite observations of atmospheric composition. In this case it is recommended that an ad hoc CBS-CAS Team of experts of satellite data for atmospheric composition monitoring be established (see tasks 3.16 and 3.17 in the GAW Strategic Plan). Statements of Guidance (SoGs) For satellite data, the development plans of satellite operators and the output of the CEOS atmospheric chemistry constellation group can be referred to. For the space-based component there are existing gap analyses, e.g. by CEOS ACC. In addition the Dossier on the Space-Based Component of the GOS also addresses atmospheric composition capabilities and gap analysis. Additionally, space agencies have carried out extensive user requirement consultations for future mission planning, which can be referred to. These have been structured around the main application areas identified in the IGACO report. A number of GCOS actions related to atmospheric composition exist. These will be reviewed to determine whether it is appropriate that they are carried forward to the EGOS-IP. User requirements Extensive work has been carried out to establish the requirements for the operational monitoring of atmospheric composition from space. It will be necessary to ensure consistency of the various sources of requirements per application area. Satellites provide information on various physical and chemical parameters with global coverage. Due to different instrument types and ageing of instrument components, and bearing in mind the radiative transfer modeling uncertainties, a thorough and comprehensive validation of satellite data by referenced ground-based observations is mandatory. It should therefore be an integral part of satellite missions. Users expect data that are quality-controlled, preferably shortly after the measurement. Validation should therefore be implemented as an operational process. The user requirements for ground-based observations are fully addressed in the IGACO strategy for the different focus areas and, as a consequence, in the latest GAW strategy.

WIGOS, the RRR, and the Vision for WIGOS in 2040

WIGOS, the RRR, and the Vision for WIGOS in 2040 Lars Peter Riishojgaard WIGOS Project Office, WMO Secretariat WMO; Observing and Information Systems Department) Overview 1. Brief introduction to WIGOS