CryoClim – A service for climate monitoring of the cryosphere

Summary of project development per November 2011

Date 15 November 2011

Project ref. Contact Web

ESA/NSC PRODEX CryoClim cryoclim@cryoclim.net www.cryoclim.net

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Executive summary

Air temperature measurements show a clear trend of global climate warming during the last decades. The Arctic temperature has increased at almost twice the rate compared to that of the rest of the world over the same period. It has been generally agreed internationally that climate monitoring is urgently needed in order to quantify and better understand the climatic changes taking place. Recognising the needs of climate monitoring as stated by UNFCCC and the implementation plan provided by GCOS, the CryoClim project was established in 2008 by the Norwegian Space Centre (NSC) in collaboration with the European Space Agency (ESA).

The vision of the CryoClim project is to develop a new operational and permanent service for long-term systematic climate monitoring of the cryosphere. The product production chains and the corresponding product repositories are hosted by mandated organisations, and the service is to be delivered through a state-of-the-art portal solution accompanied by a number of web services supporting both human and machine users. The system and service is a contribution to the Global Earth Observation System of Systems (GEOSS) and the Global Cryosphere Watch (GCW) according to the climate monitoring principles recommended by the Global Climate Observing System (GEOS).

The final project phase intends to complete the sub-services, produce the full time series of cryospheric products and establish a system for operational production to continuously update the product sets (in near real-time for sea ice and snow). The system will be completed with an operational backend system (including machine interfaces) and with a frontend, which includes a portal. The whole system will finally be operationalized, aiming for a permanent service for cryospheric climate products.

The CryoClim project is carried out by Norwegian Computing Center (NR), Norwegian Meteorological Institute (METNO), Norwegian Water Resources and Energy Directorate (NVE) and Norwegian Polar Institute (NPI). The project is funded by NSC and managed by ESA under the PRODEX programme.

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Contents

1  CryoClim vision and status ................................................................................................ 5 

2  The product model .............................................................................................................. 6 

2.1  Cryospheric baseline product model ........................................................................... 6 

2.2  Climate-change indicator product model ..................................................................... 6 

3  The product portfolio .......................................................................................................... 7 

4  Sub-service for sea ice........................................................................................................ 8 

5  Sub-service for snow .......................................................................................................... 9 

6  Sub-service for glaciers mainland Norway ..................................................................... 10 

7  Sub-service for glaciers Svalbard .................................................................................... 11 

8  The portal ........................................................................................................................... 12 

9  The web service ................................................................................................................. 13 

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1 CryoClim vision and status

The vision of the CryoClim project is to develop a novel operational and permanent service for long-term systematic climate monitoring of the cryosphere. The product production system and the product repositories are hosted by mandated organisations, and the service is to be delivered through a state-of-the-art web portal and web service. The portal includes functionality for searching, viewing and downloading. The machine interface makes the CryoClim service accessible from other web services and applications. The service is free of charge. The databases are connected over the Internet in a seamless and scalable network, open for inclusion of more databases/sub-services. The system and service is a contribution to the Global Earth Observation System of Systems (GEOSS) and the Global Cryosphere Watch (GCW) according to the climate monitoring principles recommended by the Global Climate Observing System (GEOS).

The project currently develops sub-services for sea ice and snow products of global coverage and glacier products covering Norway (mainland and Svalbard). The current project partners are the Norwegian Computing Center (NR; project coordinator), Norwegian Meteorological Institute (METNO), Norwegian Water Resources and Energy Directorate (NVE) and Norwegian Polar Institute (NPI).

The project is now starting the fourth and final project phase. At this stage the project has developed the first (incomplete) version of the web service and portal, mostly completed the sub-service for sea ice, developed the passive microwave component and essential parts of the optical snow sub-service, made almost two full glacier product coverages for mainland Norway based on optical data and implemented SAR-based algorithms for glacier monitoring in Svalbard. The final project phase intends to complete the sub-services, produce the full time series of cryospheric products and establish the fully operational production to permanently update the product sets (in near real-time for sea ice and snow). The web service and portal will be completed with a fully operational backend system.

CryoClim system concept, which is based upon a fully decentralised system concept

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2 The product model

There are two main product types provided by CryoClim:

Cryospheric Baseline (CB) products: Spatial products, maps, of climate variables

Climate-change Indicator (CI) products: Analysis result of a time series of observations (usually from baseline products) suitable to assess changes over time

Every product is viewable in the portal and available for downloading for further processing. Each product comes with a set of metadata.

2.1 Cryospheric baseline product model A CB product is characterised by an aggregation period and a set of layers. The aggregation periods may typically be:

Day Week Month Season (December-January-February; March- etc.) Year

Observations are collected and averaged for the given period of time. Variable aggregation might in many cases be useful for studying climate changes at various time resolutions and makes processing of longer time series of data more manageable. It may also be necessary for achieving full geographical coverage, in particular for optical sensors which are limited by cloud cover.

The typical layers of a baseline product are:

Average Minimum Maximum Standard deviation Number of observations Flags (warnings, etc.)

There might be more or less layers depending of the characteristics of the actual cryospheric variable and the means of observing it by remote sensing. Most baseline products are provided in the netCDF CF file format.

2.2 Climate-change indicator product model The CI product model is not as strict as the CB product model. A climate-change indicator product is typically a result of an analysis of a time series of CB products where the result might be plotted as a graph easily visualising potential changes over time. Typical examples are glacier area or length plotted as a function of time. Another example is the maximum or minimum Arctic sea ice area plotted as a function of time. These products are provided in Microsoft Excel format or as comma-separated lists.

In some cases a climate-change indicator product is more suitable represented as a spatial (map) product. An example is the change of the length of the snow season per grid cell as they are defined by the baseline product for snow cover extent.

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3 The product portfolio

The table below shows the current CB product portfolio. The column ECV refers to the Essential Climate Variables (ECVs) as defined by GCOS. Each product group is briefly commented in the following.

The table below shows the current and currently envisioned CCI product portfolio. The actual product portfolio will be discussed with potential users and tailored according to the feedback.

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4 Sub-service for sea ice

The sea ice products are based on the EUMETSAT Ocean Sea Ice Satellite Application Facility (OSISAF) developed and delivered by METNO and the Danish Meteorological Institute (DMI). The OSISAF daily observations are aggregated into climate products by the CryoClim service.

The Sea Ice Concentration (SIC) product (fractional area covered by sea ice within a grid cell) is based on the passive microwave radiometers SMMR for the period 1979-1987, and on SSM/I for the period 1987-present. The Sea Ice Edge (SIE) product is based on SIC by applying a 15% SIC threshold.

Currently, a full time series of products has been processed. Only monthly aggregated products are available by now. The products cover extended Arctic and Antarctic regions.

Average Sea Ice Concentration (SIC) for January 1979 based on SMMR

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5 Sub-service for snow

There are three snow products under development; all for Snow Cover Extent (SCE) (snow/no snow within a grid cell). The single-sensor products based on passive microwave radiometers and optical sensors are intermediate products where we aim for a final multi-sensor product based on a combination of passive microwave and optical radiometers.

There is currently a time series of passive microwave products available based on the SSM/I sensor for the period 1987 until present. An extension of the time series using the passive microwave radiometer SMMR for the period 1978-1987 is under consideration. A first prototype optical SCE product has been developed. This product is based on the AVHRR sensor (GAC data). The multi-sensor product will be developed in 2012.

Snow Cover Extent (SCE) from 15 January 2010 based on SSM/I

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6 Sub-service for glaciers mainland Norway

The glacier products for mainland Norway are Glacier Area Outline (GAO), Glacier-dammed Lake Outline (GLO) and Glacier Periodic Photo series (GPP). GAO is the areal extent of the glacier, GLO is defined as lakes that are attached to the glacier and GPP are in situ photos delivered “as is”.

The products are based on the Landsat TM and ETM+ sensors. A time series of GAO and GLO products are based on satellite images ranging back to 1982. As cloud cover is a limiting factor, most glaciers are only covered two times in the period 1982 until present. The current status is that the whole area has been covered once in the period 1999-2006, and most of it once for the period 1982-1999.

GAO and GLO are represented as polygons in vector format (Esri Shapefile) as this is more convenient and conformant with practices in the glacier community than the use of grid data. GPP are image files in JPEG format coming together with a textual description.

Glacier Area Outline (GAO) and Glacier-dammed Lake Outlines (GLO) for the Svartisen in mainland Norway based on Landsat TM data from 1999

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7 Sub-service for glaciers Svalbard

The glacier products for Svalbard are Glacier Area Outline (GAO), Glacier Surface Type (GST) and Glacier Balance Area (GBA). GST is a map of the surface categories glacier ice, superimposed ice, firn and not classified. GBA is a map of a glacier area that is strongly correlated with the mass balance.

GAO is based on aerial photos and SPOT images acquired in 2007–2008. The other products are based on C-band SAR data from ERS-1, ERS-2, Envisat and Radarsat. The spatial resolution is 30 m, and the time series starts in 1992. The aim is to map each glacier once a year for GST and GBA. GAO is currently available for the whole Svalbard as one map representing the current status. GST has been produced for a selection of glaciers. GBA is under development and should be available in early spring 2012.

GAO is represented as polygons in vector format (Esri Shapefile). GST and GBA are represented in grid format (netCDF files).

Glacier Area Outline (GAO) in the Ny-Ålesund area of Svalbard for three different periods

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8 The portal

The product portfolio will be available through a portal and a machine-readable interface. As the portal is under development, not all functionality is implemented and there are bugs and limitations. Also, not all products are available yet, and products are not yet available for all aggregation periods. There is still a need for harmonisation of metadata, the use of colours, etc.

Note that the portal is currently running on a virtual machine, so it might take up to a minute before it is loaded after activation.

The screen copy of the portal user interface below illustrates the concept the portal is based on. There are four tabs in the upper left corner providing various functionality and information:

Search: This is where the search criteria are specified.

Results: The list of products found based on the search criteria come up here.

Basket: This is the “shopping basked” where you can store various search results until further processing or downloading. There will also be functionality for product subscription. (Basket functionality is not yet implemented.)

Documentation: Various documents for downloading in PDF, such as user manuals, validation reports and GCOS compliance statements. (Documents are not yet available.)

Help: The “helpdesk”, where the product producer or service provider can be contacted. (Help functionality is not yet implemented.)

The web portal interface for spatial products, here Sea Ice Concentration (SIC)

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9 The web service

Several machine interfaces have been implemented. Most focus has so far been given to metadata interfaces as this is an opportunity to announce products in a wider context.

Metadata are served using OAI-PMH supporting metadata standards Dublin Core, GCMD DIF and ISO19115. Metadata are also served using OGC CSW serving ISO19115. Implementation of SRU (ISO23950) interface serving ISO19115 is on-going. When both interfaces are in place the CryoClim system will have interfaces both towards INSPIRE and WMO Information System frameworks.

An open issue concerning metadata is the granularity of metadata. Metadata is used both for discovery purposes as well as for internal purposes linking the various nodes of the CryoClim system. One problem experienced is the relation between discovery metadata and actual files, a relation that is required to establish distributed services. This issue has been brought up with governing bodies for metadata and some solutions are now being tested.

Data can be accessed using HTTP and OpeNDAP. OGC WCS support is still at beta level and patches for handling polar data submitted to the software used has yet not been implemented in the software. Updates to datasets are communicated using RSS feeds and email notification upon the users’ choice.

The CryoClim backend system

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www.cryoclim.net

Norwegian Computing Center (NR) P.O. Box 114 Blindern NO-0314 Oslo Contact person: Rune Solberg E-mail: rune.solberg@nr.no Role in project: Project coordinator, snow retrieval, system development

Norwegian Meteorological Institute (met.no) P.O. Box 43 Bindern NO-0313 Oslo Contact person: Mari Anne Killie E-mail: mari.a.killie@met.no Role in project: Global sea ice and snow services, system development

Norwegian Water Resources and Energy Directorate (NVE) P.O. Box 5091 Majorstua NO-0301 Oslo Contact person: Liss Marie Andreassen E-mail: lma@nve.no Role in project: Glacier service for mainland Norway

Norwegian Polar Institute Polar Environmental Centre NO-9296 Tromsø Contact person: Max König E-mail: max.koenig@npolar.no Role in project: Glacier service for Svalbard

CryoClim is funded and managed by

the European Space Agency and the Norwegian Space Centre