Aerodrome MET Observation and Forecast Discussion 2024 Jan 23 - team-sx/iwxxm-sx GitHub Wiki

Details

2024-Jan-23, 14:45-15:45 UTC, Webex

Agenda

  1. Collaboration on developing aerodrome MET observation and forecast information services.
    • Time frame of FMI's own project
    • How can the development of IWXXM schemas fit into FMI's work plan
    • How can the development work align with the respective activities under WG-MRAD and WG-MIE.

Notes

  1. Regarding expectation of the outcome:
  2. Regarding IWXXM WxObject:
    • Basically a 4D bounding box characterized by properties
    • The properties normally include a MET parameter and associated metadata. If the WxObject intends to represent a phenomenon, it can involve more than one MET parameter and associated metadata
    • There isn't any constraint on the representation of a MET parameter and its metadata, which can be scalar, vector, matrix, sequence, time series, etc. While we may want to use predefined complex types (see discussion) for properties, we may want to be careful not to overwhelm the simplicity and flexibility of WxObject with sophisticated complex types. As a matter of fact, WxObject is practically a simplified form of OGC O&M which is an overkill in representing parameters like pressure.
  3. Regarding MET parameter representation:
    • Provision of a sequence of primitive data Vs consolidated data
      • 120 1-second wind data Vs a 2-minute mean wind - There is no known use case on user consolidation of primitive data
      • Having said that, Choy have encountered some advanced users who would like to get a 2-minute mean wind and the 120 1-second wind data used for the aggregation in order to examine wind fluctuation within the 2-minute period. However, this was related to researches and is unlikely to be required in current day-to-day operations
      • In case there is a need to let user consolidate primitive data, there will be a need to let them know a suitable methodology for aggregation through the use of metadata
      • From information service perspective, an API can be created for real-time aggregation, for example, of 1-second data into a 2-minute mean. This is out-of-scope regarding development of information model
    • FMI's provision of tabular aerodrome forecasts
      • They are basically time series of forecast MET parameters
      • Currently the MET parameters are provided at fixed time intervals, but this is not necessarily the case in general; forecast interval could be down to 15 minutes in the first few hours of the forecast period and up to 12 hours a few days after. Translating into data format requirement instead of providing a single time step and then a series of MET parameter at each of the time step we may need to use a series of tuples to contain both the time and MET parameter
      • There are also probability forecasts. However, as the probability value is the probability of an outcome or research result given the hypothesis (e.g. chance of exceeding certain threshold), additional metadata will be required to adequately represent the concept
    • Segregation of MET parameters from reporting practices
      • For TAC because of the need to provide concise information in a message of limited length, data which may have spatial and temporal variation within the reporting period may need to go through additional consolidation. Examples can be found in METAR (e.g. prevailing visibility, round-down of RVR values and "marked-discontinuity" in wind reporting) and TAF (e.g. change group criteria). In provision of future aerodrome observation and forecast information we may want to consider to re-factor reports by providing the original MET parameters as well as contributions regarding reporting practices (e.g. time when "marked-discontinuity" occurs)
    • Representativeness and use of multiple sensors
      • Currently only one representative value will be given for a MET parameter. We may want to consider the need to provide supplementary information regarding other sensors that may be used in the calculation (as well as the methodology being used) or provide greater representativeness of the spatial and temporal coverage involved

Actions

Nil.

Next Meeting

In mid to late Feb.

Attendees

  • BL Choy
  • Dirk Zinkhan
  • Joonas Eklund
  • Ilkka Rinne