Use of EO data to calculate severe weather thresholds

Project Aims

The overarching aim of this project is to develop an improved approach for using Earth Observation (EO) or other publicly accessible data to demonstrate whether ground at a specific location is frozen or has snow cover, with a reasonable level of accuracy and consistency.

To achieve this the project will need to explore data available, issues regarding its use for this purpose, and comparative results from trialling different approaches. A secondary aim of this project is to provide JNCC with confidence that the proposed method is effective, and equipping JNCC with evidence that outcomes resulting from use of the approach are robust to stand up to potential challenge.

Project Background

JNCC runs the 'Severe Weather Scheme' (SWS), to provide a trusted mechanism to advise on the restriction of shooting of wildfowl and waders for conservation purposes during extended periods of severe weather, specifically when ground is frozen or snow covered. During such periods birds are naturally more vulnerable as it is harder for them to feed, whilst at the same time their energy requirements for survival are high. JNCC runs the scheme in collaboration and consultation with the country nature conservation bodies, environmental NGOs and shooting organisations. Information from the scheme is used to inform the Secretary of State, who has the power to impose a statutory suspension of shooting activities in all or part of GB under the Wildlife and Countryside Act 1981 Section 2(6).

The Severe Weather Scheme monitors temperatures annually to determine if a suspension of shooting activities is advised. The scheme runs during the open season for shooting any of the relevant species, i.e. the period from 7th November to 20th February. In addition to providing information to inform statutory suspensions of shooting, the scheme also advises wildfowlers on 'voluntary restraint of shooting' and wider guidance on activities that could disturb birds such as watersports and dog walking.

The SWS has been running since the early 1980s. Criteria as to what severity of freezing weather should trigger voluntary restraint or a statutory suspension was originally agreed by a working group comprised of ornithological and data experts from the British government's nature conservation advisory body, and non-governmental organisations representing shooting and conservation interest. The agreed criteria relied on manual daily checks at a selection of weather stations as to whether ground was frozen or covered in snow. In 2001, with increasing automation of weather stations, the manual checks were replaced with automated temperature threshold readouts of grass and air temperature, as a proxy to indicate frozen or snow covered ground. For many years the SWS has operated using these data provided by the Met Office, but the Met Office are now stopping the provision of these data, so an alternative approach is required.

JNCC has done some preliminary light touch investigation of the feasibility of using data from Earth Observation (EO) and other sources as an alternative to data collected in situ by a network of Met Office ground weather stations. JNCC has piloted use of EU METOSAT Land Surface Temperature (LST) data in combination with Met Office forecast air temperature, but has noticed accuracy and consistency issues in the approach trialled. JNCC's initial investigations will be provided to the successful contractor to consider and inform their review and further investigation.

Specific details of the criteria currently used in the SWS are available on the JNCC website. In essence, the SWS may trigger a shooting suspension - either voluntary or statutory - based on whether more than half of a network of weather stations in England/Wales (considered as a single unit) and/or Scotland report 'frozen' conditions (i.e. grass temperature below -2°C and air temperature below 1°C) for a set number of consecutive days or more, allowing for some short periods of thaw in between.

Knowledge and experience of EO datasets and data processing is essential for this contract. Ornithological expertise is less important, noting that we are not proposing changing the core criteria of what would trigger action, merely focussed on investigating alternative options for how we judge if the criteria have been met. JNCC can provide the limited ornithological input that may be relevant to consider, for example on the optimal geographic locations to consider to replace the existing weather station network.

The total budget available for this project including VAT is £25,000.

Project Objectives

Objective 1 - Reviewing data sources

To review data sources that are available to meet the project aim.

The data sources must have the following features:

• Effective in assessing ground state: Currently the scheme uses data for both air temperature and grass/ground temperature as a proxy for frozen or snow covered ground to achieve this robust assessment. Data sources may replace this information or include other relevant metrics.
• Low cost: The data sources must be easily obtainable at low cost or free at point of access.
• Timeliness: Data relating to the state of the ground that morning or over the course of the previous night should ideally be available before 10:00 each day to facilitate timely decision-making. The current scheme requires continuous recordings of night-time temperatures specifically between 21:00 each night to 09:00 the following morning.
• Location: The scheme must provide localised data covering England, Wales and Scotland. The existing SWS uses point locations at a network of Met Office weather stations currently used in the scheme, but there is flexibility around this going forwards. For example, it may be that use of average temperate over a wider area surrounding each weather station is more appropriate to use when using EO data. In addition, polygons of relevance could be selected on the basis of bird density or shooting pressure as opposed to being focussed around the existing weather stations included in the scheme. The successful bidder should discuss this aspect with JNCC who can provide ornithological guidance.
• Transparent: Since the outcomes from this scheme may influence legislative action, it is important that the data it is based on is from a trusted/transparent source and open to scrutiny. Ideally the data would be in the public domain, or at least available to the public at low cost.
• Archival capability: Data must be archived for reference.

We note, that JNCC have considered the option of setting up a new manual scheme using volunteers or contractors to take manual ground state observations daily through the season, but has ruled this out due to issues such as the cost and risk of data disruption (e.g. if volunteers were ill).

Objective 2 - Trialling and evaluating approaches

To trial use of the most promising data source(s) and evaluate how effective they are at assessing the state of the ground, and how similar the outcomes for the SWS would be. Data from the current scheme is available for use in back casting comparisons.

The ultimate intention is for the method to be run as a service to routinely monitor whether severe weather measures should be implemented. Therefore, the evaluation should also consider whether the approach(es) could be reliably be used for this purpose.

A recommendation should be provided on the optimal approach for the SWS.

Project Objectives: Detailed Tasks

Objective 1 detailed tasks:

A light touch literate review is required. The search strategy and information to be recorded from each paper or data sources should be proposed to JNCC at the start-up meeting, for input and agreement, before work commences. JNCC will provide the successful bidder with their initial scoping work to build on. It would also be welcomed if the contractor could draw on their own expert EO knowledge.

Where possible, the review methodology should align with the 'quick scoping review' and/or 'rapid evidence review' guidance provided at www.gov.uk/government/publicati… ↗

The list of papers and data sources screened, included/excluded, and any relevant raw notes relating to each paper reviewed should be shared as an output. In addition, findings should be written up into a short summary that could be included within a technical report at a later date if required.

Objective 2 detailed tasks:

The contractor must carry out trials using data to evaluate the effectiveness of the most promising approach(s). The number of approaches to consider should be informed by the outcome of the literature review and the contractors expert opinion of the approaches that are most likely to be successful. The approaches to be considered should also be agreed with JNCC before detailed work commences.

The contractor will need to familiarise themselves with the criteria used in the existing approach for the SWS and how it is applied. One approach is that alternative datasets will provide outputs that mimic the current criteria of grass temperature