TerraClim – online terrain and climate spatial decision support systems

by | Jun 1, 2019 | Winetech Technical, Viticulture research

Assess your environment and tell your story using maps in TerraClim. The TerraClim platform is an integrated resource database with a user-friendly interface, where users can obtain pertinent information about climate, terrain and soils to aid long- and short-term agricultural decision-making.

Is it all doom and gloom?

Average global temperatures across land and ocean surfaces continue to increase at an alarming rate, with 18 of the 19 warmest years in the 138-year record (1880 – 2018) having occurred since 2001. The warmest year on record is 2016, followed by 2017, 2015 and 2018, respectively. Annual warming seems to be driven by the warming in the first and last four months of a year. The January temperatures of the last four years ranked among the five highest on record. Africa had its fourth highest continental temperatures on record in 2018, with many coastal countries experiencing droughts in the recent years. From a regional perspective, the Western Cape has been experiencing a warming trend of between 1 – 2°C (for the period 1984 – 2015). These increases are driven by maximum temperature increases and temperatures are projected to increase further, by as much as 1.5°C along the coast and 3°C inland by 2050. Conditions are exacerbated by a decreasing trend in annual rainfall over the last decade, with the past few seasons experiencing the most severe drought in 100 years. Climatic indices used to summate the seasonal growing temperatures have showed significant increases. This trend is continuing and is shifting the climate zone demarcations for viticulture. However, in the context of climate change, seasonal summations are not enough to quantify the impact of temperature shifts on the grapevine. A higher temporal resolution of weather conditions are required, as the most significant increase in temperatures are in the months of December, January and March. Compounding this is an increase in seasonal variability, which is changing the tempo of growth and ripening, grape composition and occurrence of diseases. Over recent years, the seasonal adaptations required to meet these conditions have resulted in the average industry production cost being higher than the producer’s income, often resulting in reduced new investment, long-term vineyard establishment and in extreme cases, farm closure/sales. Temperature data required at a daily/hourly interval are needed to better understand these changes and to inform adjustments of existing practices.

Understanding proceeds action

In view of climate change, economic pressures and limited water availability in the agricultural sector, information about the suitability of land for viticulture is paramount to aid long- and short-term decision-making. A 2017 survey conducted among researchers, consultants and producers highlighted the need for accessible data that can support decisions at farm and field level. The absence of a single, integrated database with a user-friendly interface, where viticulturists can obtain pertinent information about climate, as well as terrain and soils, was cited as one of the main obstacles for preparing for the transition of the South African wine industry, necessitated by climate change. However, continuous monitoring of environmental conditions is hampered in the Western Cape by four factors, namely:

  • The expense and logistical difficulties in performing frequent ground-based surveys over an extensive production area.
  • The sparse and irregular distribution of existing weather stations.
  • The inaccessibility (cost) and poor quality of existing weather station data.
  • The province’s complex terrain, which complicates the modelling of the dramatic local climatic variations observed in many wine producing areas.

The edgy difference

With the continued goal to improve the understanding of how the climate in the Western Cape is changing and how the grapevine is responding to these changes, the primary aims of the TerraClim project are threefold:

  1. To create a comprehensive database of long-term climate data [in collaboration with weather station custodians, namely iLeaf (http://www.ileaf.co.za/)], standardised in a flexible, query-ready format.
  2. To use this database, in conjunction with very high resolution digital elevation models (DEMs) developed by Stellenbosch University and GeoSmart Space, to interpolate wall-to-wall climate layers at a high enough resolution to inform decision-making at a field level.
  3. To present these climate surfaces as an easy-to-use online mapping tool, the TerraClim website, which allows users to view, query and draw reports of environmental and climatic variables at a field or farm level.

Supporting this, the TerraClim project has a strong climate research and development (R&D) component. One task is to make use of multi criteria analyses to identify areas where the extension of the existing weather station network should be prioritised. Building and updating a long-term and semi-real-time climate database is another important R&D activity. The database will allow for dynamic mapping, statistical interrogation, data mining, machine learning and climate change analyses over time. Additionally, TerraClim both depends on and supports other platforms in the agriculture sector, sharing information across platforms to ensure that researchers, consultants and farmers have access to the best resources for informed decision-making.

How to make informed decisions using TerraClim

TerraClim has been designed with different agricultural stakeholders in mind, and it is hoped that the platform will be beneficial to winemakers, land owners, farm managers, consultants and researchers alike. The technology is easy to use and requires only a personal device with internet connectivity. Anyone who has used Cape Farm Mapper or Google Earth will be familiar with the web-mapping format, where a user can geographically navigate to a location of choice and then select the specific data they wish to view. Users can also click on specific fields (vineyard blocks) and draw a report containing a range of maps, including high resolution climatic and topographic data (Figure 1).

FIGURE 1. Description of the possible high resolution climatic and topographic data that can be extracted from TerraClim online spatial decision support system at the selection of a specific field.

Essentially, TerraClim interpolates weather station/logger point data to produce a continuous climate map (surface) of a region to improve our understanding of the environment in space and time. Easily accessible climate layers enable one to see what is happening at vineyard block level in semi-real-time (Figure 2) or, with the accumulation of this information, on a seasonal or multiyear basis (Figure 3). Furthermore, current seasonal trends can be contextualised against previous seasons and long-term averages to aid long-term decision-making in the context of climate change.

FIGURE 2. The current TerraClim extent on 1 January 2016 at 8 am in the morning, providing easily accessible semi-real-time spatialised climatic information to aid in season decision-making.

FIGURE 3. Hourly temperature maps for a 24 hour cycle to identify the temperature dynamics of a specific area and to contextualise this information on a seasonal or multiyear basis.

The future is bright

While TerraClim is still in the pilot phase, the integration of climate and terrain data in an online web application at a field level is a solid foundation for exciting new developments. Our ultimate goal is to develop a platform that brings researchers, consultants and farmers together to discuss subjects, such as remote sensing, geography, climate and crop responses, to aid adaption to a changing environment and mitigating (possibly even harnessing) its effect on production.

Let data communicate through maps!


The purpose of TerraClim is to address one of the main obstacles faced in all agricultural sectors, namely limited access to high-resolution climate and terrain data for mitigating the effects of climate change on agriculture. TerraClim presents maps of climatic and geographic datasets presented as a series of dynamic map layers. The maps can be visualised and overlaid for any given area, similar to a geographical information system (GIS). TerraClim has a strong research and development component. This includes frequently updating and extending the climate and terrain databases, automated data collection and interpolation protocol development, as well as extensions of existing logger and weather station networks. This tool allows the wine industry, and the agricultural sector in general, to better understand the complexity of the Western Cape’s climate and terrain at a higher spatial (geographical) resolution for improved adaptation to climate change. This will help producers to stay economically sustainable and to make strategic decisions about future production decisions.

TerraClim has been funded by Winetech and seasonal weather data has been provided from iLeaf.

– We encourage anyone to engage with the early (beta) version of the TerraClim website, https://sungis10.stb.sun.ac.za/climate/,
and provide feedback to Tara Southey at tara@sun.ac.za.


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