Community-based wind erosion monitoring across Australia 1

October 2016

Dust activity Some minor dust in the south west

Wind strength Windiest October since 2005

Groundcover Good but dropping in the west

Rainfall Average to slightly above average

Land management Spring fallowing and sowing

Dust activity

There was little dust activity in October 2016 (Figure 1). This is expected due to the excellent current

groundcover across southern Australia (Figure2). Most Natural Resource Management areas within the

DustWatch network are still close to 100% of their area above 50% groundcover (Table 1).

Dust was observed at Lameroo and Walpeup on 30 October. This event was associated with very strong

westerly winds (>50km/h). Only a very small proportion of the Mallee (<1%) was below 50%

groundcover; however, bare paddocks upwind of the Walpeup site are clearly visible on the MODIS

image (red circle in Figure 2). This bare soil could be avoided by using chemical fallowing. Dust was also

detected on that day in Moree. Wind speeds where not as strong as in Walpeup and winds were from

the north. Bare paddocks ready for cotton sowing were the likely source.

Figure 1: Hours of dust activity (number in brackets) at each DustWatch site in October 2016

Community-based wind erosion monitoring across Australia 2

Groundcover

The area with greater than 50% groundcover has remained very close to 100% (Table 1) across the

network area. The biggest area below 50% groundcover is in the north west of the Local Land Services –

Western Region around Tibooburra. Due to the very high stone cover in this area dust emissions are not

likely in the near future.

Isolated bare paddocks are visible in the Local Land Services – North West Region, the South Australian

MDB Catchment Management Authority and the Mallee Catchment Management Authority area in

Victoria. These have caused isolated dust events in these areas despite the overall good groundcover.

Figure 2: Groundcover for October 2016 as determined from MODIS data.

Table 1: Percentage NRM area with groundcover >50% for May to October 2016 as determined from MODIS data.

Date Central West

Mallee Murray North Central

North West

Riverina SA MDB Western Central Tablelands

May 2016 99 92 100 100 96 99 92 83 100

Jun 2016 100 99 100 100 98 100 98 96 100

Jul 2016 100 100 100 100 99 100 99 97 100

Aug 2016 100 100 100 100 99 100 98 94 100

Sep 2016 100 100 100 100 99 100 98 96 100

Oct 2016 100 99 100 100 99 100 96 88 100

Community-based wind erosion monitoring across Australia 3

Groundcover change

Over the last three months (July 2016 to October 2016) groundcover has both increased and decreased

across southern Australia. The Local Land Services – Western region saw a decline in groundcover

(orange arrow in Figure 4); predominantly along the river corridor around Bourke and between Broken

Hill and Mildura (Figure 3). In contrast the Local Land Services – North West region saw a substantial

increase in groundcover in the grazing areas between Walgett and Moree (Figure 3). This increase in

cover is speckled in between with paddocks that declined in cover – most likely due to preparation for

cropping. The overall area above 50% groundcover for the North West region has remained steady at

99% even so large areas have either increased or decreased in cover. This emphasises the importance

of looking not only at the statistics of an area but also at the spatial distribution of the change.

Figure 3: Groundcover change between May 2016 and October 2016 as determined from MODIS data.

Figure 4: Groundcover trend for the Western LLS and Mallee and SA-MDB CMA as determined from MODIS data.

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Rainfall

New South Wales recorded variable rainfall in October 2016 ranging from 5 mm for most of the Local

Land Services – Western region to 400mm for the eastern end of the Local Land Services – Murray

region (Figure 5). Large areas in the wheat / sheep belt received between 50 and 200mm (green colours

in Figure 5). The South Australian Murray Darling Basin area received between 100mm in the south to

5mm in the north.

Figure 5: Rainfall totals for October 2016

Rainfall across the DustWatch network was average to slightly above average in October 2016 (white

and light blue colours in Figure 6a). Due to the very heavy falls in the past two months large parts of

Australia are still in the wettest 10% of Bureau of Meteorology records when looking at the last three

months (Figure 6b).

Figure 6: Rainfall deciles for October 2016 (a) and 1 July 2016 to 30 October 2016 (b)

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MODIS satellite

Fire numbers in October 2016 increased substantially from last month. In particular in the Local Land

Services – Central West and North West regions (Figure 7). This is due to the much dryer conditions and

thunderstorm activity. In additional some hazard reduction burning occurred in eastern New South

Wales.

Figure 7: Active burning fires in October 2016 as determined from MODIS satellite.

From the engine room

We are eagerly awaiting the delivery of the latest edition of the TSI DustTrak – the Environmental

DustTrak or EDT. This instrument type will soon replace some of the aging instruments that are well over

10 years old.

Social media The dust in the south west in late October 2016 occurred during daylight hours but there was no activity on social media concerning this dust event or any other dust storm in Australia.

The DustWatch team Contact us at dustwatch@environment.nsw.gov.au The MODIS image is courtesy of MODIS Rapid Response Project at NASA/GSFC; the fire data is courtesy of the Fire Information for Resource Management System (FIRMS) and the rainfall maps are from the Australian Bureau of Meteorology. This project would not be possible without funding from: the National Landcare Programme, Riverina, Western, Central West, Central Tablelands and Murray Local Land Services (LLS) in NSW; the NSW EPA, the Mallee and North Central CMAs in Victoria and Murray Darling Basin NRM in South Australian and in-kind contributions from Griffith University in Queensland, CSIRO, TERN and the Australian National University. We particularly thank our many DustWatch volunteers who provide observations and help maintain the instruments. ISSN - 2206-3161 OEH 2016/0720