Data Requirements for Aerosol Observations

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1 Data Requirements for Aerosol Observations Ellsworth J. Welton NASA Goddard Space Flight Center Will focus on contributing networks Namely GALION (I am the co-chair) MPLNET/AERONET Site: Windpoort, Namibia

2 Aerosol Measurement Variables: GAW Implementation Plan (Box 7.1) - Multi-wavelength aerosol optical depth - Mass concentration in two size fractions (fine, coarse) - Mass concentration of major chemical components in two size fractions - Light absorption coefficient at various wavelengths - Light scattering and hemispheric backscattering coefficient at multi-wavelengths - Aerosol number concentration - Aerosol number size distribution - Cloud condensation nuclei number concentration at various super-saturations - Vertical distribution of aerosol backscattering and extinction - Detailed size fractionated chemical composition - Dependence of aerosol variables on relative humidity RRR: update of aerosol data TT-ObsReq Workshop Summary In preparation: Forecasting Atmospheric Composition Community white paper on observation requirements This effort is ongoing and final result from Aerosol SAG is pending RRR must be finalized before significant data management discussion can continue (so there is my out to focus on contributing network issues)

3 Current Aerosol Requirements from OSCAR: A common theme is that vertical distribution requirements are confusing. The outcome of the RRR process will impact GALION contribution to GAW.

4 WMO Global Atmospheric Watch (GAW) Aerosol Lidar Observation Network (GALION) GALION is a lidar network of networks. It is composed of individual lidar networks, most have become official contributing networks to GAW. Many lidar networks are mature (17+ years) and pre-date GALION. GALION Networks: EARLINET AD-NET CIS-LINET regional LALINET CORALNET CREST MPLNET (global) NDACC (global) Active GALION Sites GALION Co-Chairs: Gelsomina Pappalardo (CNR IMAA) Ellsworth J. Welton (NASA) Steering Committee: Individual Network Heads Working Groups: Quality Assurance Methodology Technology Data Centers Applications GAW Report 178 (2008): GALION

5 Aerosol vertical requirements and GALION: Waiting on RRR but Lidars contribute to many aerosol variables, not just backscatter and extinction profiles. There are also missing aerosol variables for vertical distribution in current OSCAR/WIGOS and RRR documents in review. Finally, lidars provide data beyond just GAW-aerosol. Critical Missing Data: Aerosol Layer Detection and Height (most basic info & important) Backscatter and Extinction profiles are not the best proxy for aerosol layer detection Separate algorithms exist to detect aerosol layers and heights. Retrieving backscatter and extinction is more difficult, especially for ceilometers and backscatter lidars If an aerosol layer can be detected but extinction retrieval fails, how to transmit that information without a variable to store it? Potential impact to operational forecasting centers if such info is not in WIGOS? GALION contribution outside GAW-aerosol: Cloud heights, ice determination & phase Aerosol-Cloud interaction. Lidar data provide direct evidence of interaction. PBL height proxy: mixed layer depth (aerosol gradients) Critical for chemical transport and air quality Research ongoing in other areas, some examples: Infer tropopause height from high cloud detection Lidar profiling of light rain events, estimate rain drop size & fall rate Unclear to me what role our obs will play outside GAW-aerosol requirements

6 GALION is composed of multiple contributing networks to GAW Several GALION networks already have their own very mature (+17 years) data centers. The existing data centers provide multiple network specific functions beyond just data archive, discovery, browsing and download. e.g. data communications, site management, calibration services, QC/QA, funding-agency specific needs, custom applications for certain users, etc. This issue is probably not unique to GALION As a contributing networks, GALION networks must operate their own data centers. One issue is the large number of them to coordinate within GAW. In addition, we need to simplify access to lidar data for our related user communities and standardize our variables & file formats. Thus we seek to build a unified GALION data portal/center.

7 GALION Data Center: Data Discovery, Common Product/Formats, and Download The GALION steering committee (network heads) agreed last year to begin work on a unified GALION data center. Coordinate the GALION member data center efforts with GAW and the user community. GALION data center working group Welton recently added to ET-WDC Establish initial metadata content, and call for input (started in 2016) Working Group meeting planned at ILRC June 2017 Develop common data products & file format (similarity between EARLINET & MPLNET) QC & QA flags to handle heterogeneous instruments & retrieval techniques Determine data center approach: centralized vs distributed approach (portal host?) Coordinate GALION members metadata input to GAWSIS

8 GALION Data Center: Step One --- Metadata Collection (underway) Initial round. Refine within GALION then work on integration with WIGOS

9 GALION Data Center Considerations (perhaps some cross-over with other contributing networks?) Balance existing network product suites & user community needs. Can the unified GALION data center provide data discovery and delivery of all products that the individual data centers do? If not, then would the GALION data center provide enough capability to justify the effort to build it? Example: If GALION data center capability is limited to only delivering RRR approved GAW aerosol requirements, (for instance, only extinction right now), then its possible this effort would produce only a subset of what the individual network data centers already provide to a large user community (~17+ years).

10 Concluding Thoughts on Aerosol Data Observation Requirements: Aerosol variables and requirements from current RRR must be finalized before significant data management discussion can continue. Particular attention should be paid to vertical distribution requirements to alleviate existing confusion in OSCAR/WIGOS consider some method/system to identify aerosol layers independent of aerosol extinction. Perhaps detailed flag for extinction or new variable/requirement. Contributing Network data and GAW requirements Will the GAW RRR produce a list of variables/requirements that result in only utilizing a small portion of the contributing network capabilities? Or will GAW utilize full suite of contributing network products? If only a small portion, what is the benefit to the contributing network to put forth the effort? GALION: Progress from several working groups to date (here I focused on data) ILRC June 2017 Lidar Networks session: serves as GALION meeting this year Data center work began last year Metadata collection effort underway Working group meeting at ILRC in June Goal: formulation of initial unified data center framework, circulation to GALION for comment