MSGID: 1:317/3 62e42051   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
   July 29, 2022 - Water in Lake Gairdner   
      
      Water in Lake Gairdner and Island Lagoon   
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      South Australia is considered to be the driest of all the Australian   
      states, with annual rainfall topping 10 inches (250 mm) in only about   
      one-fifth of the region. Summertime (December to February) is the   
      driest and hottest season, with most rainfall in winter (June to   
      August).   
      
      As a result of the hot, dry climate, the landscape of South Australia   
      is speckled with salt lakes, most of which are little more than   
      rarely-moistened, mineral-crusted depressions. Many of these are found   
      north of the Eyre Peninsula, surrounded by the red sand hills near the   
      Gawler Ranges. The largest of these lakes—indeed the third-largest salt   
      lake in Australia—is Lake Gairdner. Lake Gairdner, along with Lakes   
      Harris and Everard, are so unique that they are protected as part of   
      Australia’s Lake Gairdner National Park.   
      
      The bone-dry, extremely flat surface of Lake Gairdner is a place where   
      land speed records are set by cars, trucks, motorcycles, and even   
      wind-driven land yachts. It’s also the location where enthusiasts meet   
      to see just how fast they can accelerate on “the big white dyno”,   
      especially during the Dry Lakes Racer’s Australia (DLRA) “Speed Week”   
      held at the end of each summer, when conditions on the giant salt flat   
      is always perfect. Always—except for this year. In 2022, Lake Gairdner   
      was under water. On February 1, the DLRA cancelled the event, citing   
      that the lake was under about 500 mm (19.7 in) of “very dirty water”.   
      
      South Australia suffered an extremely wet summer. On January 22, 2022,   
      multiple media outlets reported a “once in a lifetime” rain event,   
      which dumped 181 mm (7.1 in) at Mt. Ive in three days, which was sixty   
      percent more than its annual average. The Australian Bureau of   
      Meteorology (BOM) was quoted as saying that several spots in the state   
      had received “all-time” highest recorded rainfall totals over 24 hours,   
      with at least seven of those located near the Eyre Peninsula. A section   
      of the Olympic Dam Highway, a road that runs north of Lake Gairdner,   
      was washed away. The BOM attributed the rare summer deluge, at least in   
      part, to tropical moisture brought to Australia by then ex-Tropical   
      Cyclone Tiffany, which had crossed the northern part of the country   
      shortly prior to the southern downpours.   
      
      The torrential rainfall also filled all of the normally salt-encrusted   
      lakes in the region, including Lake Gairdner. While rain patterns have   
      returned to nearly normal since January, the South Australian salt   
      lakes have been slow to dry up. Evaporating is occurring, with   
      estimates of up to 100 mm (3.9 in) a month. But it will still be   
      several weeks or months before the “big white dyno” is ready to ride.   
      
      On July 26, 2022, the Moderate Resolution Imaging Spectroradiometer   
      (MODIS) on board NASA’s Aqua satellite acquired a false-color image   
      showing water-rich salt lakes. The image is centered on Lake Gairdner.   
      To the northwest of Gairdner is Lake Harris and to the southwest is   
      Lake Everard. Island Lagoon is the largest lake to the east of   
      Gairdner.   
      
      In this type of false-color image, a combination of infrared and   
      visible light (MODIS bands 7,2,1) are used help highlight water. Here,   
      vegetation appears in shades of green, with dense vegetation looking   
      very bright green, while open land is colored in shades of tan. The   
      Olympic Dam Highway, crossing the image in the northeast, is shaded a   
      gray-brown. Water within the salt lakes is colored blue, but the shade   
      varies depending on the depth. The deepest water is the darkest blue   
      and areas that are very shallow, where only a small amount of water   
      mixes in with the highly-reflective mineral crust, appear milky-blue.   
      Where a thin layer of water sits over the salt layer, or the salt is   
      thoroughly saturated, the blue tones tend to be a little muddier or   
      duller. White appears along the edge of most of the lakes, where the   
      water has completely dried to leave only mineral crust.   
      
      Image Facts   
      Satellite:  Aqua   
      Date Acquired: 7/26/2022   
      Resolutions:  1km (127.3 KB),  500m (310.2 KB),  250m (172.7   
      KB)   
      Bands Used: 7,2,1   
      Image Credit: MODIS Land Rapid Response Team, NASA GSFC   
      
      
      
   https://modis.gsfc.nasa.gov/gallery/individual.php?db_date=2022-07-29   
       
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