Global Terrestrial Network for Permafrost (GTN-P) - Protocols (good work practices)

Protocols (good work practices)

Guidelines and advice on good field work practices

Detailed documentation of field work provides the base for the usage of your data. The documentation should support and help interpret any future connected work and it should use a set of common principles, so that others consulting your field work documentation can understand and translate the information.

General protocols based on standard formats following ISO frameworks for instance (ISO TC211 for geographic information) should be applied in the entire network in order to make possible to compare data collections from different monitoring sites in different countries to each other and thus to analyse and cross the data. These standard formats should be discussed in the permafrost science community.

Read more about metadata for boreholes and active layer monitoring sites and download field sheet for metadata report for boreholes

Data schemes

When writing down your data into tabular format (f.e. Excel) a set of format rules apply which make it possible for the database to read and work with your data. These format rules are the following:

• The character set should be UTF-8 (UCS Transformation Format - 8 bit)
• Date format must be: YYYY-MM-DD hh:mm (ISO 8601)
• Measurements should be given in metric system
• Coordinates should be given in decimal degree with at least four decimals (allowing only a few meters offset). The referential system should be WGS 84 (EPSG 4326) .
• Positive values (+) should be used to indicate points below the ground
• Negative values (-) should be used to indicate points above the ground
• Use a dot (.) for decimals
• Use a comma (,) to separate columns
• Null values should be indicated by -999. 

Thermal State of Permafrost (TSP)

Permafrost temperatures are obtained by lowering a calibrated thermistor into a borehole, or recording temperature from multisensor cables permanently or temporarily installed in the borehole. Measurements may be recorded manually with a portable temperature logging system or by data loggers. The accuracy and resolution of the thermistors and measurement varies but it is desirable for accuracy to be ±0.1°C or better. Spacing of sensors on cables (or the spacing of measurments if single sensor used) generally increases with depth. For example, in the upper 5 to 10 m, sensor spacing of 0.5 to 1 m can adequately define the shallow thermal regime while spacing may increase to 5 to 10 m or more at depths greater than 20 m. However, by comparing data collections from different sites and countries to each other we recognized a great variation in the depths where measurements have been taken. In some cases, measurements have been taken at different depths in different years. In other cases, measurements have been taking at "uneven" depths given in values with several decimal places which were only characteristic for this certain site. This differentiation between depths over both space and time makes it very difficult to compare data collections with each other and thus to analyse the data. Here, a consistency over the entire network of TSP (establishing unified depths/referential depths) would be a great improvement.

Another aspect addresses the precision of variables, i.e. the time stamp of measurements (has the measurement been retrieved from one single measurement or is it an average value of a certain time period, f.e. 24 hours?).

Active Layer Thickness (ALT)

Several traditional methods are used to determine the seasonal and long-term changes in thickness of the active layer: mechanical probing once annually, frost (or thaw) tubs and interpolation of soil temperatures obtained by data loggers. 

When using a grid, a referential point should be determined from which the location of the nodes is given in offset x/y [meters]. We recommend this referential point to be in the bottom left corner. The orientation of the grid should be cardinal points (North South orientation). A consistency over the entire network of CALM would make it much easier to compare data collections to each other and thus to analyse the data.

Data User Element (DUE) Permafrost

The main purpose of the ESA DUE Permafrost project is to define, demonstrate and validate, permafrost monitoring information service from local to large scale, mainly towards climate change studies and addressing the pan-boreal/arctic zone. The service is supposed to support the GCOS implementation plan with systematic satellite-based Earth Observations of global permafrost extent, change and related products. It should further support permafrost monitoring activities of national and intergovernmental bodies and scientific groups involved in climate change research. The goal of the Permafrost project is to demonstrate EO integrated services in the field of permafrost monitoring of the boreal zone with active participation of user organisations, mainly from the scientific world.description.
Datasets on surface temperature and surface soil moisture have been included into the GTN-P Database and here is given an overview on the variables.

¹regional: Alaska, Mackenzie, Laptev Sea, Ob Estuary, Central Yakutia