Keyword

Seasonal

25 record(s)
 
Type of resources
Topics
Keywords
Contact for the resource
Provided by
Years
Formats
Update frequencies
status
From 1 - 10 / 25
  • Categories    

    <p>Digital Hemispherical Photography (DHP) upward-looking images are collected up to twice per year to capture vegetation and crown cover at Wombat Stringybark Eucalypt SuperSite. These images are used to estimate Leaf area index (LAI). The images are captured at the times of estimated maximum and minimum LAI. </p><p> The site was established in 2010 in the Wombat State Forest in Central Victoria. The site is dry eucalypt forest with main species <em>Eucalyptus obliqua</em>, <em>Eucalyptus radiata</em> and <em>Euclayptus rubida</em>. For additional site information, see https://www.tern.org.au/tern-observatory/tern-ecosystem-processes/wombat-stringybark-eucalypt-supersite/. </p><p> Other images collected at the site include photopoints, phenocam time-lapse images taken from fixed under and overstorey cameras and ancilliary images of fauna and flora. </p>

  • Categories    

    This product has been superseded and will not be processed from early 2023. Please find the updated version 3 of this product at https://portal.tern.org.au/metadata/TERN/169dbb12-846f-4536-9dab-e31378d16b41. Two fractional cover decile products, green cover and total cover, are currently produced from the historical timeseries of seasonal fractional cover images. These products compare, at the per-pixel level, the level of cover for the specific season of interest against the long term cover for that same season. For each pixel, all cover values for the relevant seasons within a baseline period (1988 to 2013) are classified into deciles. The cover value for the pixel in the season of interest is then classified according to the decile in which it falls.

  • Categories    

    <p>Digital Hemispherical Photography (DHP) upward-looking images are collected twice per year to capture vegetation and crown cover at the Warra Tall Eucalypt SuperSite. These images are used to estimate Leaf area index (LAI). The images are captured at the times of estimated maximum and minimum LAI. </p> <p> The Warra Tall Eucalypt SuperSite was established in 2012 and is located in a stand of tall, mixed-aged <em>Eucalyptus obliqua</em> forest (1.5, 77 and &gt;250 years-old) with a rainforest / wet sclerophyll understorey and a dense man-fern (<em>Dicksonia antarctica</em>) ground-layer. The site experienced a fire in January 2019, which consumed the ground layer and killed a high proportion of the understorey trees but stimulated dense seedling regeneration. For additional site information, see https://www.tern.org.au/tern-observatory/tern-ecosystem-processes/warra-tall-eucalypt-supersite/. </p><p> Other images collected at the site include photopoints, phenocam time-lapse images taken from fixed under and overstorey cameras, panoramic landscape and ancillary images of fauna and flora. </p>

  • Categories    

    The seasonal dynamic reference cover method product compares the current ground cover level of each pixel to a reference pixel based on the historical timeseries and is available for Queensland from 1987 to present. It is created using a modified version of the dynamic reference cover method developed by <a href="https://doi.org/10.1016/j.rse.2012.02.021">Bastin et al (2012) </a>. This approach calculates a minimum ground cover image over all years to identify locations of most persistent ground cover in years with the lowest rainfall, then uses a moving window approach to calculate the difference between the window's central pixel and its surrounding reference pixels. The output is a difference image between the cover amount of a pixel's reference pixels and the actual cover at that pixel for the season being analysed. Negative values indicate pixels which have less cover than the reference pixels.<br> The main differences between this method and the original method are that this method uses seasonal fractional ground cover rather than the preceding ground cover index (GCI) and this method excludes cleared areas and certain landforms (undulating slopes), which are considered unsuitable for use as reference pixels.<br> This product is based upon the JRSRP Fractional Cover 3.0 algorithm.

  • Categories    

    An estimate of persistent green cover per season across Australia from 1989 to the present season, minus 2 years. This is intended to estimate the portion of vegetation that does not completely senesce within a year, which primarily consists of woody vegetation (trees and shrubs), although there are exceptions where non-woody cover remains green all year round. It is derived by fitting a multi-iteration minimum weighted smoothing spline through the green fraction of the seasonal fractional cover (dp1) time series. A single band image is produced: persistent green vegetation cover (in percent). The no data value is 255.

  • Categories    

    <p> Digital Cover Photography (DCP) upward-looking images are collected at least twice per year to capture vegetation cover at Calperum SuperSite. These images can be used to estimate Leaf area index (LAI), Crown Cover or Foliage Projective Cover (FPC). The images are captured at the times of estimated maximum and minimum LAI.</p> <p> The Calperum Mallee SuperSite was established in 2011 and is located on Calperum Station with research plots located in mallee woodland (burnt in 2014), Callitris woodland and a river floodplain (recovering from extensive grazing), consisting of black box, river red gum and lignum. The core 1 ha plot is located in mallee woodland. For additional site information, see https://www.tern.org.au/tern-observatory/tern-ecosystem-processes/calperum-mallee-supersite/ .</p> <p> Other images collected at the site include photopoints, phenocam time-lapse images taken from fixed under and overstorey cameras, panoramic landscape and ancillary images of fauna and flora. </p>

  • Categories    

    Two fractional cover decile products, green cover and total cover, are currently produced from the historical timeseries of seasonal fractional cover images across Australia, available for each 3-month calendar season. These products compare, at the per-pixel level, the level of cover for the specific season of interest against the long term cover for that same season. For each pixel, all cover values for the relevant seasons within a baseline period (1990 - 2020) are classified into deciles. The cover value for the pixel in the season of interest is then classified according to the decile in which it falls.<br> This product is based upon the JRSRP Fractional Cover 3.0 algorithm.

  • Categories    

    The data set contains distance measures of primary (wind-borne) and secondary (on ground) seed dispersal during spring, summer and autumn, using empirical observations and detailed measurement of wind characteristics. Seeds were collected from populations of <i>Callitris verrucosa</i> within the reserve and was placed parallel to, and 100 m from the burn edge within the burnt site. For the empirical observation of seed dispersal we chose six release locations, three locations in each of the two sites, about 6 km apart that had both recently undergone a planned burn, one in spring 2009 and the other in autumn 2011. Within those two sites the three release locations were positioned 800 m apart from each other along a transect that was placed parallel to, and 100 m from the burn edge within the burnt site. To assess primary (wind-borne) seed dispersal, 20 randomly chosen seeds were released from each of three different heights (1 m, 2 m and 3 m) at each of the six sites, giving a total of 360 seeds released per season. Seeds were only released within a horizontal wind speed range of 8 - 25 km/h. At lower wind speeds seeds would not take-off and at higher wind speeds seeds could not be relocated. This data set could be reused in a similar study carried out for the same species in a different location. <br> To understand the effect of standing vegetation on the secondary (on-ground) seed dispersal, we established groups of 10 seeds on the ground within 10 m of each of the six previous release locations. Seed were left for 4 days before relocated and distances to the starting point were measured. This was repeated during all 3 seasons. Out of the 180 seeds released,161 (89%) seeds could be relocated. <br> Wind measurements were taken on a sand dune crest in the site that was burned during autumn 2011 using an ultrasonic anemometer (Model WindMaster (Part 1590-PK-020), Gill Instruments Ltd, Lymington, UK). Measurements continued for two weeks in spring, summer and autumn. The anemometer measured horizontal wind speed, horizontal wind direction, and vertical wind speed every 0.1 s, producing a dynamic, three dimensional wind speed vector. Measurements were taken at 2 m height. The data can be used for studies dealing with wind movements in mallee during Spring, Summer and Autumn as well as comparative seed dispersal studies using the same or other wind dispersed plant species.

  • Categories    

    The Sentinel-2 seasonal fractional ground cover product shows the proportion of bare ground, green and non-green ground cover and is derived directly from the Sentinel-2 seasonal fractional cover product, also produced by Queensland's Remote Sensing Centre. The seasonal fractional cover product is a spatially explicit raster product, which predicts vegetation cover at medium resolution (10&nbsp;m per-pixel) for each 3-month calendar season. However, the seasonal fractional cover product does not distinguish tree and mid-level woody foliage and branch cover from green and dry ground cover. As a result, in areas with even minimal tree cover (>15%), estimates of ground cover become uncertain. With the development of the fractional cover time-series, it has become possible to derive an estimate of ‘persistent green’ based on time-series analysis. The persistent green vegetation product provides an estimate of the vertically-projected green-vegetation fraction where vegetation is deemed to persist over time. These areas are nominally woody vegetation. This separation of the 'persistent green' from the fractional cover product, allows for the adjustment of the underlying spectral signature of the fractional cover image and the creation of a resulting 'true' ground cover estimate for each season. The estimates of cover are restricted to areas of <60% woody vegetation. Currently, the persistent green product has only been produced at 30&nbsp;m pixel resolution based on Landsat imagery, resulting in this Sentinel-2 seasonal ground cover product having a medium 30&nbsp;m pixel resolution also. This is an experimental product which has not been fully validated. This product is similar to the <a href="https://portal.tern.org.au/metadata/TERN/fe9d86e1-54e8-4866-a61c-0422aee8c699 ">Seasonal ground cover - Landsat, JRSRP algorithm Version 3.0, Australia Coverage</a> which is based on a different satellite sensor.

  • Categories    

    This dataset consists of counts for multiple plant species obtained from the Ethabuka Station and Carlo Reserve in the Simpson Desert, Australia, from 2004-2013 by the Desert Ecology Research Group (DERG) in conjunction with LTERN. It also consists rainfall data obtained from 2004-2012. These datasets were used to perform a Dynamic Factor Analyses for the manuscript, "Life form explains consistent temporal trends across species: the application of dynamic factor analysis". For more information see: DERG; https://www.desertecology.edu.au.