@article {bnh-3033, title = {Mitigating the effects of severe fires, floods and heatwaves through the improvements of land dryness measures and forecasts: Annual project report 2015-2016}, number = {174}, year = {2016}, month = {09/2016}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The Australian people, businesses and environment are all vulnerable to wildfires, floods and other natural hazards. Deloitte Access Economics (2016) estimate the 2015 total economic cost of natural disasters in Australia exceeded $9 billion. Some examples of recent extreme events are the 2015 West Australia Esperance bushfire, the 2015 South Australia Pinery bushfire, the 2009 Victoria Black Saturday bushfires, the Millennium drought spanning from 1998 to 2009 and the summer 2010/2011 floods in Eastern Australia. A recent United Kingdom Meteorological Office report concludes that investment in weather services provides around a tenfold return (Gray 2015).

Accurate soil moisture information is critical for the management and warning of fires, floods and landslips and this project addresses fundamental limitations in our ability to prepare for these events. Fire ignition, intensity and spread rate are strongly influenced by soil moisture content. Knowledge of soil moisture is essential for the accurate prediction of wildfire incidence and the occurrence of large destructive fires corresponds to very large soil moisture deficit values. Soil moisture also strongly influences temperatures and heatwave development by controlling the partitioning of net surface radiation into sensible, latent and ground heat fluxes. Rainfall forecasts are crucial for many applications and many studies suggest that soil moisture can significantly influence rainfall.

Currently soil moisture, for fire danger prediction, is estimated using very crude models developed in the 1960s that oversimplify the calculation of evapotranspiration and runoff leading to significant errors. These crude models do not take into account different vegetation properties, soil types, terrain and many other factors. They are poor drivers of the models used by fire agencies, and the Bureau of Meteorology to predict dangerous fire conditions as the science is outdated and has been verified as not effective (Dharssi and Vinodkumar 2015).

Soil moisture can have very high spatial variability due to the very high spatial variability of vegetation properties, soil textures, orography and rainfall. Therefore, it is highly desirable to analyse soil moisture at the highest possible spatial resolution. Many applications, such as fire danger warnings, agriculture and weather forecasting, require soil moisture information at a spatial resolution of 5 km or better. A state of the art, high resolution soil moisture information system is under development with daily updating and a spatial resolution of 5 km. The system provides information on 4 soil layers. The top layer is 10 cm thick and the total thickness of the soil column is 3 m. Verification against ground based soil moisture observations and a case study show that this prototype system is significantly more skillful than the over-simplified models currently used operationally. This new system will significantly improve Australia{\textquoteright}s ability to manage multiple hazard types and create a more resilient community.

}, issn = {174}, author = {Imtiaz Dharssi and Vinod Kumar} }