GRWG/GDWG Web Meeting 2013-09-24

GSICS Web Meeting on GSICS Requirements from SCOPE-CM Phase 2 Proposals

Agenda (UTC times)

11:00 Introduction to SCOPE-CM (Marie)

11:30 Calibration related SCOPE-CM projects (plans + anticipated contributions from GSICS)

- Advancing the status of the AVHRR FCDR (K-G Karlsson)

- Inter-calibration of passive imager observations from time-series of geostationary satellites (IOGEO) (Roebeling)

- Land surface albedo from geostationary satellites (LAGS) (Alessio)

- Sustained production of the International Satellite Cloud Climatology Project (ISCCP) cloud products (Ken Knapp)

12:30 Discussion

- anticipated contributions from GSICS

- inclusion of additional GSICS members in SCOPE-CM projects

13:00 List of actions

Attendees

Guest Chair: Rob Roebeling (EUMETSAT)

CMA: Lin Chen

EUMETSAT: Rob Roebeling, Bartolomeo Viticchie, Alessio Lattanzo, Marie Doutriaux Boucher, Viju John, Sebastien Wagner and Tim Hewison

JMA: Keita Hosaka and Masaya Takahashi

KMA: Dohyeong Kim

NOAA: Fangfang Yu, Manik Bali, Ken Knapp

SHMI: Karl-Göran Karlsson

Summary

Introduction to SCOPE-CM (Marie)

Marie gave a general introduction of SCOPE-CM, providing information about its high level goals, the mechanisms to achieve these goals, and the current status of SCOPE-CM. She indicated that SCOPE-CM is now in its second Phase, for which 10 SCOPE-CM projects have been selected by the SCOPE-CM executive panel. All these projects aim at generating Climate Data Records of Fundamental or Thematic (Essential Climate Variables) parameters. Moreover, these projects aim to improve the system maturity, describing the practises used to generate these CDRs, of the data records. Marie highlighted that there are 4 SCOPE-CM activities that involve inter-calibration of satellite radiances, i.e.,

1. Advancing the status of the AVHRR FCDR,
2. Inter-calibration of passive imager observations from time-series of geo stationary satellites (IOGEO),
3. Land surface albedo from geostationary satellites (LAGS), and
4. Sustained production of the International Satellite Cloud Climatology Project (ISCCP) cloud products.

During this TC these projects are presented, and potential involvement of GSICS in these projects is discussed.

Advancing the status of the AVHRR FCDR

(K-G Karlsson) (presented by Rob) summarized the plans for the AVHRR-FCDR project. Within the CM-SAF the FCDR of AVHRR-GAC data from the PATMOS-X project has been used for reprocessing of their cloud retrievals (CLARA-A1). The first reprocessing revealed several issues with the input FCDR (quality of reference satellite calibration, infra-red calibration, navigation, and data housekeeping). This SCOPE-CM project aims to resolve these issues and to improve the quality of the AVHRR-GAC FCDR.

This project has several links to GSICS. Firstly, GISCS is interested to follow the approaches adopted to perform the VIS and NIR recalibration and to propagate these calibrations back in time. Second, this SCOPE-CM project is interested in the approaches used by GSICS using IASI observations for the recalibration of the IR channels, as well as the approach GSICS is developing that uses HIRS observations to recalibrate the time-series of MFG and MSG observations of the IR and WV channels. The link is related to the work outlined in the SCOPE-CM IOGEO project.

Further to this presentation the following actions were defined:

Action EUMETSAT: Keep SMHI informed about the progress on preparing a reference HIRS data record. When this dataset is ready it can be made available to the SCOPE-CM AVHRR-FCDR project.

Action SMHI: Keep GSICS informed on the methods adopted by the CM-SAF for calibrating the VIS and NIR channels of the AVHRR-GAC time-series.

Inter-calibration of passive imager observations from time-series of geostationary satellites (IOGEO) (Roebeling)

Rob Roebeling presented the aims and workplan of the IOGEO SCOPE-CM project. This project aims to generate a Fundamental Climate Data Record (FCDR) of the visible (VIS), infrared (IR) and water vapour (WV) channel radiances from all geostationary satellites. The re-calibration methods used in IOGEO will be based on the work done within GSICS. However, since the aim is to re-calibrate observations from all geostationary back in time till ~1982, the GSICS methods cannot be taken over one-to-one. The main constrains are that defined method should allow re-calibration of all geostationary satellites back to the 1980^th with sufficient accuracy for climate research. These constraints pose several challenges on the selected re-calibration method, i.e., a superior reference instrument needs to be available over the complete time-series, the method, or combination of methods, should be applicable to all the geostationary satellites, the re-calibration accuracy should be better than 3%.

Some anticipated involvements of GSICS in this SCOPE-CM activity are:

1. Sharing of knowledge;
2. Exchange of inter-calibration approaches;
3. Contribute to the definition of an inter-calibration approach for the IR and WV heritage channels (2014-2015);
4. Contribute to the definition of a combined inter-calibration approach for the VIS/NIR heritage channels (2015-2016);
5. Participate in the verification and validation of the FCDRs (2015-2016).

It was indicated that the IOGEO SCOPE-CM is open to additional participants from space agencies such as CMS and KMA. Rob asked CMA and KMA about their on-going activities with respect to re-calibration of their heritage instruments. CMA indicated that they will recalibrate their FY1 historic data records against AIRS and IASI. In order to cover the entire time-series of the data records and additional reference is needed. EUMETSAT indicated that using the HIRS data record might be an option of completing the entire record. Another advantage of using HIRS as additional reference is that it covers the full FY1 time-series, and thus can be useful to check temporal stability. EUMETSAT noted that the work done by CMA fits very well in the scope of SCOPE-CM IOGEO. EUMETSAT asked CMA if they would be interested in participating in SCOPE-CM IOGEO. Further to this discussion two actions were defined:

Action EUMETSAT: Invite KMA and CMA to participate in SCOPE-CM IOGEO

Action EUMETSAT: Share HIRS data record with CMA

Land surface albedo from geostationary satellites (LAGS) (Alessio)

Alessio Lattanzio introduced the LAGS SCOPE-CM project. This project aims to generate a Thematic Climate Data Record (TCDR) of surface albedo from all geostationary satellites. Key to the generation of this TCDR is a Fundamental Climate Data Record (FCDR) of visible reflectance observations. One of the first tasks foreseen within the LAGS project is the re-calibration of VIS observations from all geostationary satellites during the cause of 2014. Although this task is related to the objectives of IOGEO SCOPE-CM, its timing is out of phase with IOGEO that aims at providing such a FCDR in 2017 at the earliest. Therefore, within LAGS an intermediate solution needs to be adopted for the re-calibration methods re-calibration of the VIS channels. At the meeting it was discussed that the Deep Convective Clouds (DCC) method of GSICS could serve as baseline for the re-calibration in LAGS. Reasons are that most participants (JMA, NOAA, and EUMETSAT) are already using this method, or are familiar with the basic principles, and the method can be applied to all heritage geostationary satellite observations. For this phase of LAGS using DCC may be the most pragmatic solution. For future re-processings, LAGS may use the FCDR provided by IOGEO. The actions defined are:

Action JMA and EUMETSAT: To collaborate with EUMETSAT on transferring EUMETSAT’s DCC method to JMA through the EUMETSAT VS activity with JMA.

Action NOAA: Fangfang to establish contacts with the NOAA representative in SCOPE-CM GSA and inform them on using NOAA’s DCC for the recalibration of the time-series of GOES visible channel observations.

Sustained production of the International Satellite Cloud Climatology Project (ISCCP) cloud products (Ken Knapp)

Ken Knapp introduced the objectives of the ISCCP SCOPE-CM project. The main aim of this SCOPE-CM project is to repeat the recalibration of the ISCCP level-1 data, comprising all AVHRR and geostationary radiances of the common VIS and IR channels, and calibrate their radiances generate a homogeneously calibrated dataset of their radiances. The recalibration is done in three steps, i.e., 1) nominal calibration step, 2) normalized calibration step, 3) absolute calibration step (see Schiffer and Rossow 1985 (BAMS); Brest and Rossow 1992 (IJRS); Desormeaux et al. 1992 (J. Atmos. Ocean. Technol)). The nominal calibration is the best available information obtained from the satellite operator or the literature, usually the prelaunch calibration for the VIS channel and on-board calibration target results for the IR channel (Rossow et al. 1987). The normalized calibration reports the results of the comparison with the current afternoon polar-orbiter measurements without regard to variations in the calibration of the polar orbiter, itself. Finally, the absolute calibration accounts for any short-term changes that are found and for any changes in the calibration of the polar-orbiter radiances.

Ken formulated some questions and concerns for GSICS:

- What are the plans for recalibration of historic data records?

This question is basically answered in the above presentations on SCOPE-CM projects. There is overlap between these projects, although they either cover different datasets of have a different planning. GSICS or the SCOPE-CM secretariat may need to consider setting up a mechanism to coordinate the exchange of knowledge and methods between these projects.

- Can GSICS share their DCC code for this activity?

Sharing of the method can be done by sharing the code or by sharing the ATBD.Fangfang indicated that this is possible. This needs to be discussed further within NOAA (Fangfang and Ken) and with EUMETSAT and JMA.

Concerns:- Where to find the resources for SCOPE-CM activities?

There is no funding associated with SCOPE-CM. However, SCOPE-CM may be used as argument to find 3rd party funding within national or inter-national research funding programs. The commitments made to SCOPE-CM are not-binding, and their timely completion depends on the funding situation.

- How to reconcile different approaches?

At the meeting it was suggested that we should inter- compare the re-calibrated datasets generated within different SCOPE-CM projects and within GSICS so as to reconcile different approaches.

The actions defined are:

Action NOAA: Provide information on the ISCCP method to GSICS.

Action EUMETSAT: Share and/or keep NOAA informed on the progress made in setting up the DCC method.

Outcome

Action EUMETSAT (Rob Roebeling): Keep SMHI informed about the progress on preparing a reference HIRS data record. When this dataset is ready it can be made available to the SCOPE-CM AVHRR-FCDR project.

Action EUMETSAT (Rob Roebeling): Invite KMA and CMA to participate in SCOPE-CM IOGEO

Action EUMETSAT (Rob Roebeling) : Share HIRS data record with CMA

Action JMA and EUMETSAT (Masaya Takahashi & Sebastien Wagner): To collaborate with EUMETSAT on transferring EUMETSAT’s DCC method to JMA through the EUMETSAT VS activity with JMA.

Action NOAA (Fangfang Yu): Establish contacts with the NOAA representative in SCOPE-CM GSA and inform them on using NOAA’s DCC for the recalibration of the time-series of GOES visible channel observations.

Action NOAA (Ken Knapp): Provide information on the ISCCP method to GSICS.

Action EUMETSAT (Sebastien Wanger): Share and/or keep NOAA informed on the progress made in setting up the DCC method and applicability to ISCCP archive.

Action NOAA: Provide information on the ISCCP method to GSICS.

Action EUMETSAT: Share and/or keep NOAA informed on the progress made in setting up the DCC method.