To evaluate the data products (uncertainty budget etc.) and bring in missing knowledge
The Task Team on Radiosondes exists to provide guidelines for GRUAN on how to obtain the best possible reference quality data from radiosoundings. According to the reference specifications (Immler et al., 2010) that have been approved during the ICM-2 meeting in Payerne, "reference quality" means that a data product:
- is traceable to an accepted standard (generally to the SI unit)
- provides a comprehensive uncertainty analysis.
- is properly documented (e.g. in peer-reviewed publications) and validated (e.g. through intercomparisons).
In this context the Task Team supports efforts from manufacturers, scientists (at sites) and the GRUAN Lead Centre to take the steps that are necessary to obtain reference quality in radiosoundings, i.e. to choose suitable sensors, to define correction algorithms and QA/QC procedures, to identify and quantify sources of uncertainty, to define data formats for submission, and to provide proper documentation of this entire chain including technical documents and peer-reviewed publications.
To draw conclusions on the suitability of the deployed equipment
The GRUAN Global Navigation Satellite Systems (GNSS) precipitable water (GNSS-PW) Task Team (TT) was established in summer 2010 as one of then six GRUAN TTs. TTs are charged with addressing critical GRUAN requirements. Ground-based GNSS-PW was identified as a Priority 1 measurement for GRUAN, and the GNSS-PW TT’s goal is to develop, update and assist implementing explicit guidance on hardware, software and data management practices to obtain GNSS-PW measurements of consistent quality at all GRUAN sites.
To develop defensible, quantifiable, scientifically-sound guidance
The task team on measurement schedules aims to develop defensible, quantifiable, and scientifically-sound guidance for GRUAN sites regarding measurement schedules and associated site requirements, in order to meet all GRUAN objectives including climate trend detection, satellite calibration/validation, and studies of local meso-scale processes and events. Working out an optimal mix of measurement strategies that best serves these combined calls on the network will require careful consideration of a number of factors beyond the purely technical ones. Due to the fact that site resources will differ across the network, it will be necessary to produce a number of different and scalable strategies that can be utilized by sites possessing varying technical resources. These strategies must be backed up by quantitative evidence to the extent possible, and should apply to both in-situ and remote sensing capabilities.
Representing GRUAN sites
The task team on site intercommunication and reporting exists to provide and maintain a convenient mechanism for each GRUAN site to communicate with other sites, the WG-GRUAN and the Lead Centre, and for the WG-GRUAN and Lead Centre to disseminate information to all GRUAN sites through their task team representative. Each site is encouraged to have one representative on this task team and if possible, to provide other task teams with knowledgeable members such that each site has wide-ranging representation within GRUAN. The task team on site intercommunication and reporting should include a shared member from the task team on measurement schedules, preferably from an institution/program that is under-represented within GRUAN, so that each task team is promptly informed about any recent activities of the other.
The success of GRUAN is critically dependent on the efficiency of communication between sites, the WG-GRUAN and the Lead Centre. Sites experiencing problems, concerns, breakthroughs in best practices and/or important discoveries are expected to initially communicate these to the task team on site representation. After internal discussion, the task team will communicate this information to the appropriate GRUAN representatives.
With initial focus on MWR, Lidars and to interface with NDACC
The task team on Ground-Based Remote Sensing Measurements (GBRS) exists to define protocols, sampling strategies and required metadata for respective suites of ancillary ground based remote sensing measurements routinely collected and archived at GRUAN sites. Ancillary in this respect is defined as measurements at a given GRUAN site that do not fall under the set of required observations from all sites, for example the reference radiosonde. Ancillary in this sense also includes required respective instrument calibration, inter-validation strategies and results and all metadata pertinent to the deployed equipment and associated measurement suites. These shall be compiled utilizing best measurement practices as defined through associated measurement international expert team representation in this group. Practices and protocols for respective measurement suites as defined by this group shall constitute guidelines for respective site and measurement certification.
The task team on satellites evaluate and document the potential of relevant satellite instrumentation as well as long-term data sets that are available. These shall be assessed and compiled utilizing best measurement practices as defined through associated measurement international expert team representation in this group. These assessments will, where applicable, include GRUAN developed metrology standards for uncertainty estimates and their application to improve the usability of satellite records.
This task team will thus continue to closely cooperate with the ancillary measurement task team, but it will also tailor work more towards the use of GRUAN data for satellite instrument calibration and validation, as well as the use of satellite data to improve GRUAN products.