Community-based wind erosion monitoring across Australia 1

DustWatch Report September 2018 Dust activity Increased in the north-east and south-west NSW Wind strength Less windy than the last 10 years Groundcover Reducing; especially in western NSW Rainfall Below average for most of NSW Land management Low rainfall providing challenges to cropping and grazing

Dust activity September 2018 saw heightened dust activity in the north east of New South Wales (Figure 2) between Bourke, Armidale and Dubbo. The south west between Coombah and Deniliquin saw similar dust activity. It was the third dustiest September in the last 13 years (Figure 1). The dust originated from the Darling River Plains and the Lake Eyre Basin lake systems. Severe dust events, visible from satellite (Figure 10), occurred on 15 September 2018, driven by very strong westerly winds. The hours of strong winds were much lower than expected for September, thus preventing more dust.

Figure 1 Area for Western Local Lands Services with above 50% groundcover (orange line) and monthly hours of dust (blue line) – September data only

Figure 2 Hours of dust activity (number in brackets) at each DustWatch site in September 2018

05101520253035404550

0102030405060708090

100

Sep 2005Sep 2006Sep 2007Sep 2008Sep 2009Sep 2010Sep 2011Sep 2012Sep 2013Sep 2014Sep 2015Sep 2016Sep 2017Sep 2018

Aver

age

hour

s of d

ust h

aze

(h)

Area

abo

ve 5

0% g

roun

dcov

er (%

)

Community-based wind erosion monitoring across Australia 2

Groundcover The area above 50% groundcover (green colours in Figure 3) has reduced slightly from August 2018 (Table 1). The Local Land Services – Western Region has seen a significant reduction in the area above 50% groundcover, especially west of the Darling River and in the Willandra west of Ivanhoe. However, it has a greater area above 50% groundcover than September 2009.

Figure 3 Groundcover for September 2018 as determined from MODIS by CSIRO Table 1 Percentage of each NRM with groundcover >50% for September 2017 to September 2018 as

determined from MODIS Date Central

West Mallee Murray North

Central North West

Riverina SA MDB

Western Central Tableland

s Sep 2017 99 100 100 100 97 100 97 76 100

Oct 2017 99 99 100 100 98 100 94 67 100

Nov 2017 97 96 100 100 95 99 89 58 100

Dec 2017 95 92 99 100 93 96 84 51 100

Jan 2018 93 94 99 100 93 96 86 51 100

Feb 2018 92 94 99 100 93 95 86 53 100

Mar 2018 93 95 99 100 93 95 88 55 100

Apr 2018 96 96 99 100 95 97 91 62 100

May 2018 96 97 100 100 95 99 95 68 100

June 2018 97 99 100 100 96 100 98 72 100

July 2018 96 99 100 100 95 100 96 68 100

Aug 2018 93 98 100 100 93 99 94 59 100

Sept 2018 91 97 99 100 92 97 88 50 100

Community-based wind erosion monitoring across Australia 3

Groundcover change Significant groundcover reductions between June 2018 and September 2018 (red colours in Figure 4) occurred in the north of New South Wales between Dubbo and Moree and in the Local Land Services Riverina, Murray and Western regions. The area above 50% cover has dropped for all areas (Figure 5). Groundcover has increased in the south eastern cropping country of New South Wales between Griffith and Wagga Wagga (green colours in Figure 4). The increases in the ground cover within cropping areas are not as wide spread as they should be at this time of the year, indicating failing winter crops; especially in the west of the State.

Figure 4 Groundcover change between June 2018 and September 2018 as determined from MODIS

Figure 5 Percentage area of NRM with more than 50% cover since September 2005 as determined

from MODIS

25

50

75

100

Sep

2005

Sep

2006

Sep

2007

Sep

2008

Sep

2009

Sep

2010

Sep

2011

Sep

2012

Sep

2013

Sep

2014

Sep

2015

Sep

2016

Sep

2017

Sep

2018

Area

abo

ve 5

0% g

roun

dcov

er (%

)

Central West

Mallee

Murray

North Central

North West

Riverina

SA MDB

Western

Central Tablelands

Community-based wind erosion monitoring across Australia 4

Groundcover across New South Wales was much lower in September 2018 when compared with September 2017 (Figure 6). When comparing September 2018 to September 2009, the year of the ‘Red Dawn’ dust storm, groundcover values are lower than 2009 in the north-east of the State, especially in the Local Land Services North West and Central West regions (red colours in Figure 7). Groundcover is better in the south of New South Wales (green colours in Figure 7) and north of Broken Hill.

Figure 6 Groundcover change between September 2017 and September 2018 as determined from

MODIS

Figure 7 Groundcover change between September 2009 and September 2018 as determined from

MODIS

Community-based wind erosion monitoring across Australia 5

Rainfall Welcome rainfall was recorded for the eastern parts of New South Wales (Figure 8) with falls exceeding 10 millimetres recorded east of a line from Moree in northern New South Wales to Loddon Plains in northern Victoria. These falls were average for this time of the year in the north east but most of the State remained in the driest 10% of rainfall records for the month of September (Figure 9a). This also means that most of New South Wales remained in the driest 10% of Bureau of Meteorology (BoM) records for the last three months (Figure 9b). Updates on the latest drought status across the state can be found on the Department of Primary Industries website at: Latest NSW Drought maps.

Figure 8 Rainfall totals for September 2018 (source: Bureau of Meteorology)

Figure 9 Rainfall deciles for September 2018 (a) and 1 July 2018 to 31 September 2018 (b)

Community-based wind erosion monitoring across Australia 6

VIIRS fires and MODIS satellite image The number of fires in September 2018 (3879 pixels with temperature anomalies) was almost identical to September 2017 (3801 pixel – Figure 11). Fire numbers in the Local Land Services Western Region were high for the month of September. This is likely due to lightning strikes and the very dry conditions. The satellite image also shows the dust storm that occurred on Saturday 15 September 2018 (red circles in Figure10). This dust travelled east later that day and affected coastal communities.

Figure 10 Pixels (375m) with active burning fires in September 2018 as determined from VIIRS satellite

Figure 11 Number of 375 m pixels with active burning fires between January 2016 and September

2018.

The DustWatch team Contact us at dustwatch@environment.nsw.gov.au Dust data supplied by the Office of Environment and Heritage Rural Air Quality network. The MODIS image is courtesy of MODIS Rapid Response Project at NASA/GSFC; the VIIRS 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, 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 OEH2018/0009

0100020003000400050006000

Jan-

16Fe

b-16

Mar

-16

Apr-

16M

ay-1

6Ju

n-16

Jul-1

6Au

g-16

Sep-

16O

ct-1

6N

ov-1

6De

c-16

Jan-

17Fe

b-17

Mar

-17

Apr-

17M

ay-1

7Ju

n-17

Jul-1

7Au

g-17

Sep-

17O

ct-1

7N

ov-1

7De

c-17

Jan-

18Fe

b-18

Mar

-18

Apr-

18M

ay-1

8Ju

n-18

Jul-1

8Au

g-18

Sep-

18

Number of 375m pixel detected by VIIRS instrument Central Tablelands

Central West

Mallee

Murray

North Central

North West NSW

Riverina

SA MDB

Western