THE CLIMATE KELPIE BLOG: Climate tools developed with farmers for farmers

Posted by BCG on 20th September 2021

Exciting times lie ahead for farmers using seasonal forecast information to make on-farm decisions with the advent of new forecast products which will become available on the Bureau of Meteorology website from later this year. This has been made possible through a five year (2017-2022) nationwide project, ForeWarned is ForeArmed (FWFA), funded by the Australian Government Department of Agriculture, Water and the Environment’s Rural R&D for Profit program with co-investment from 14 project partners. Researcher partners have been working closely with farmers from across Australia to deliver state-of-the-art forecasts beyond the traditional seven-day weather forecast so that farmers can make more informed decisions when it comes to extreme weather and climate events.

Dr Debbie Hudson, Principal Research Scientist at the Bureau of Meteorology, said these tools couldn’t have come soon enough: “Compared to most of their international competitors, Australian farmers face a high level of year-to-year variability in climate. There are many ways to build resilience to the variable climate, including improved plant varieties and animal genetics, new ways to monitor plants and soils and utilising existing multi-week and seasonal forecasts. However, we recognised, and were being told by producers, that something more was needed.”

“By working with producers and farm consultants we have been able to efficiently collect feedback on what forecast information was lacking and develop new forecast products in consultation with users. Industry reference groups from the dairy, red meat, grains, sugar and wine sectors have played a critical role in the development of the new forecast products in this project. This includes providing feedback on user-needs for seasonal forecasting, as well as the impact of forecasts on farm decision-making,” Dr Hudson said.

“The value of information lies in its use. Forecasts are only valuable if they provide the information that farmers need, if they are issued when famers are making their critical decisions and if they can help inform a decision.”  

The Bureau of Meteorology provides multi-week and seasonal climate outlooks for rainfall and temperature over Australia. Most of these forecasts are focused on the middle of the distribution of possible outcomes, for example forecasts of the chance of above median conditions. However, this does not provide any indication of the risk of extreme conditions, such as an extended period of extreme heat, or a decile 1 (bottom 10%) rainfall season. Five new multi-week and seasonal forecast products developed in the FWFA project will become available to the public and will help producers better prepare for the onset of extreme climate events. These five products were chosen through consultation with farmers from a large set of experimental prototypes developed during the project.  

The NEW tools 

There are five new products that will be listed on the bureau website over the coming months.

Product #1  

The first product is maps showing the chance of having extreme rainfall, maximum temperatures or minimum temperature for the weeks, months and seasons ahead. These maps are a natural extension of the bureau’s currently available probability of above median maps and show the chance of having very wet, dry, hot or cold conditions. For example, Figure 1 shows the forecast issued at the end of August of the chance of having an extremely dry spring season (September to November 2021). For these maps “extreme” has been defined as being amongst the driest, wettest, hottest or coldest 20% of periods (weeks/months/seasons) from the climatological (historical) period (i.e., deciles 1 & 2 (bottom 20%) or deciles 9 & 10 (top 20%)).

Figure 1: Extreme Rainfall Map. Example of the chance of having an extremely dry spring (amongst the bottom 20% in the climatology period). The forecast shown here is for the Sept-Oct-Nov 2021 season and is suggesting a low risk of having decile 1 or 2 rainfall totals over much of the eastern two thirds of Australia (probabilities are less than the usual risk of 20% over large areas). Over much of Western Australia (areas shown in white), the chance of a really dry spring is no different to long term odds of 20%, except for a few areas (shown in the various shades of brown) where there is an increased risk of a really dry spring.

Product #2  

The second product is the “decile bars”. These are location-specific bars that indicate the shift in the probabilities compared to usual across the deciles. They are available for rainfall, maximum and minimum temperatures for the weeks, months and seasons ahead. Figure 2 shows an example of the bars for a forecast of monthly and seasonal rainfall. These were one of the most popular products that arose from consultation with producers and advisors. 

Figure 2: Decile bars. Rainfall forecasts for Wagga Wagga for upcoming months and seasons (generated on 30 August 2021). The forecasts show the probabilities across five different decile ranges. The long-term average probability (“usual chance”) for each category is 20% and the forecasts show the shift in the odds compared to usual. For example, for October, the odds are stacked towards having a wetter month than usual in Wagga Wagga, with about double the usual risk of having a decile 9 or 10 rainfall (i.e., being amongst the top 20% of wettest Octobers).

Product #3  

The third product is the “climagram”. These are location-specific timeseries graphs showing the forecast of rainfall totals, maximum and minimum temperatures respectively for the coming weeks and months. Past observations are also shown on the graph. Insight from producers and advisors really drove the creation of this product due to the strong desire to visualise the forecast as a time-series for a given location (rather than having to look at multiple maps). The forecasts of rainfall totals and temperatures (rather than departures from normal) facilitates flexibility for temperature/rainfall threshold-specific decisions. 

Figure 3: Climagram. Timeseries of observed (red solid line) and forecast (red box plots) maximum temperature (y-axis) for consecutive weekly periods (x-axis) for Birchip. The box plots indicate the range in the expected outcomes from the forecasts. The grey shading indicates the usually expected temperatures for that time of year (based on 1981-2010). The thresholds shown for the box plots and the grey shading are the 10th, 25th, 50th (median), 75th and 90th percentiles. For example, Week 1 (30 August-5 September 2021) is forecast to have a weekly mean maximum temperature of around 21.5°C (the median of the forecasts), which is much warmer than usual (e.g., the median line of the box is above the median line of the grey shading and is even higher than the 90th percentile of usually expected temperatures). In contrast, in Week 3 temperatures are expected to return to close to usual, with a weekly mean maximum temperature of ~19°C i.e., the median of the forecasts which is close to the historical median).

Product #4  

Probability of exceedance (POE) graphs for rainfall are the fourth product and probably the most complex of the new tools to understand. However, once understood through the consultation process with producers and advisors, the overwhelming feedback was that this tool is valuable and will allow users to delve deeper into the forecast information. It forms part of a hierarchy of complexity of forecast tools. Insight from the producers in the reference groups indicated that for some users this information is too detailed, but for others, it could provide very useful input into their decision-making. Figure 4 shows an example of a POE forecast. The POE curves give the probability (y-axis) that different thresholds of rainfall (x-axis) will be exceeded at the location in question. The curves slope from the top left down to the bottom right, because as the rainfall totals increase, the probability of exceeding those totals decreases. The black curves are for the forecast POE and the grey curves are for the historical POE (i.e. climatology). Comparing the black and grey curves indicates how different the forecast is from usual conditions. The forecast product gives users the flexibility to identify the rainfall threshold that they are interested in on the x-axis, and then read off the associated probability of exceeding that threshold on the y-axis (or vice versa). 

Figure 4: Probability of Exceedance. Example forecast for rainfall, showing the forecast (black) and usual conditions (grey) for Adelaide during the period of 30 August to 5 September 2021.

Product #5  

The final product is the 3-day rainfall accumulation (or “burst”) forecast which is a map-based product and available for multi-week forecasts (see Figure 5). The forecast product shows the likelihood (probability) of receiving a pre-selected threshold of rainfall over three consecutive days in the upcoming weeks or fortnights. The experimental product currently has four thresholds that can be selected but it will be possible to add more thresholds.

Figure 5: 3-day rainfall accumulation (burst) product. A forecast map showing the probability of receiving an intense ‘burst’ of rainfall over a short period of time. For example, in this map parts of western Tasmania and coastal Queensland have a greater than 75% chance of receiving more than 30mm of rainfall in three days during 30 August to 5 September.

The examples shown above are all research-quality prototypes of the forecast products. The next phase of the project involves another round of feedback with users to enhance the display and look-and-feel of the products and their supporting information in preparation for their release on the Bureau website. The products will become available to the public in a staged approach between October and June next year.   

This project is supported by funding from the Australian Government Department of Agriculture, Water and Environment as part of its Rural R&D for Profit program in partnership with rural Research and Development Corporations, state departments and universities. Meat & Livestock Australia (MLA) is responsible for the overall management of the project. 

Click here to watch a video about the Forearmed is Forewarned Project.

For more information contact:

Debbie Hudson, Debbie.Hudson@bom.gov.au 

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