Saturday, 21 December 2013

Wednesday, 31 July 2013

More action from Australia

Tuesday saw us back at Karawatha Forest park to collect SALCA data along side the Riegl VZ400 and Faro instrument. In addition to the laser scanner data the the team are collecting field spectrometer data to characterise the spectral properties of leaves and bark. Sampling the upper canopy requires the use of an oversize slingshot which propels bean bag and string into the canopy; the bean bag wraps around branches and these are then pulled down for sampling - sometimes it works, and sometimes it goes wrong!

Steve Hancock and Andrew Burt (University College London) attempt to untangle the sling-shot string!
Rachel and Mat Disney (University College London) use an ASD Fieldspec to measure leaf reflectance and transmittance
 Short clip of SALCA in action - the noise of the generator wins over the birdsong for most of the clip

Monday, 29 July 2013

SALCA goes to Australia

The SALCA team is in Brisbane, Australia, taking part in an international terrestrial laser scanner inter-comparison study. The experiment has been organized as part of the TLS International Interest Group (TLSIIG) formed at Silvilaser in Vancouver last September. We are joined teams from the US and Australia to compare the data from a range of different TLS instruments for measuring forest canopy structure at two sites close to Brisbane.

The University of Boston and University of Massachusetts have brought the Dual Wavelength Echidna Lidar (DWEL) and the short range but handy Canopy Biomass Lidar (CBL), the Queensland Government Department for Science, Innovation, Technology, Innovation and the Arts (DSITIA) and TERN (University of Queensland) a Riegl 400VZ, and the University of Southern Queensland a Faro Focus 3D.

First obstacle overcome: SALCA makes it in one piece to Australia much to the relief of Mark, Steve, Rachel and Lucy
After spending a day carrying out calibration measurements in the lab we collected the first field data today at Karawatha Forest Park just south of Brisbane. The plots we are using are part of the Australian Terrestrial Ecosystem Research Network (TERN) and the field experiments are coordinated by John Armston (DSITIA) and Glen Newnham (CSIRO). They have done a great job and we had over 30 scientists in the field today.

Another first for the SALCA team: Lucy looks pleased after collecting the first dual wavelength TLS data in the southern hemisphere!
Glen Newnham (CSIRO) takes a close look at SALCA
More on the TLSIIG experiments from TERN here

Sunday, 30 June 2013

SALCA down on the farm

June saw SALCA return to Newcastle for NERC-funded field experiments testing the sensitivity of the instrument to changes in canopy moisture content. The (literal) field experiment, involving 22 potted trees at the University’s Cockle Park Farm, involves repeated SALCA scans as drought stress is induced in groups of trees over a period of 1 month, alongside scans of regularly watered controls. The SALCA signal will be compared to a range of physiological measurements and to spectral data acquired with an ASD field spectrometer. The experiment is now well under way, and after initial teething problems with windthrow and over inquisitive and hungry livestock, the drying groups of small-leaved lime (Tilia cordata) and Austrian pine have been gradually wilting for a little over a week. Steve has got to grips with the operation of a cherry picker and fingers are crossed that the so far almost ideal weather will last! Early results from the experiments will be presented in a poster at INTECOL, London in August. 

Setting up the experiments
What happens when sheep get hold of a windblown experimental tree, and a possible culprit.

Clockwise: SALCA in the field, a small-leaved lime drying group with intensity calibration board, measuring stomatal conductance and contact probe measurments of leaf reflectance properties.

Thursday, 18 April 2013

First Prize for Lucy

New team member Lucy Walker presented her research ideas at the recent "Wavelength" conference of the Remote Sensing and Photogrammetry Society, at Glasgow University 11-13 March 2013. She presented a poster describing the SALCA instrument, its measurement capabilities and characteristics, and some of her initial experimental results. The conference was attended by around fifty participants and included both key-note speakers and poster sessions. 

Lucy's poster was very well received and she was awarded a prize for the best poster at the conference. Congratulations Lucy!

Wednesday, 20 March 2013

SALCA @ Newcastle

2013 kicked off with another new addition to the SALCA team. Steve Hancock (previously at Swansea University) started work as a Postdoctoral Research Associate at Newcastle University as the latest NERC grant got under way  The project is examining the potential of dual-wavelength laser scanning for monitoring leaf moisture content at canopy scales through both laboratory and small-scale field experiments at one of the Newcastle University farms.  The initial project meeting, including project partners from Salford (Mark Danson, Lucy Walker) and UCL (Mat Disney, Andrew Burt), was held in January, providing a useful opportunity to catch up on progress, introduce new members of the team and make future plans. Since then Steve has been busy planning experiments and these are now under way  with SALCA on loan from Salford University for the next month. Priorities include examining leaf-level responses from a variety of species (including conifers) and undertaking laboratory-based scans of small trees.  Other efforts (at Newcastle and Salford) are focussed on code and model development to improve data analysis and understanding of the SALCA signal. Expect more soon from Steve as he starts to produce some preliminary results!

Steve, with SALCA, at Newcastle University

Tuesday, 5 February 2013

SALCA paper in Remote Sensing of Environment

We are pleased to say that the results of the leaf drying experiments described earlier in the blog, and some additional modelling work, have now been published online in Remote Sensing of Environment. The paper demonstrates a good relationship between a normalised ratio of the two SALCA wavelengths and leaf equivalent thickness and shows the values of this ratio to be in-line with those expected based on PROSPECT leaf optical properties modelling. It represents the first test of an active laser scanning instrument for measuring leaf moisture content. The challenge now of course is to scale this up to canopy levels - lots more to come on that over the next few months!

You can read more in the final article available online:
Gaulton, R., Danson, F.M., Ramirez, F.A. and Gunawan, O. (2013). The potential of dual-wavelength laser scanning for estimating vegetation moisture content. Remote Sensing of Environment, 132, 32-39.