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Christopher Nankervis [LinkedIn + PhD Thesis]

Contact:  s0094337@staffmail.ed.ac.uk

www: terrabyke.com
Find me on ... LinkedIn

I am a Meteorology postgraduate student at the University of Edinburgh. I form part of the Global Change Group. My PhD is funded by NERC and supervised by Dr Hugh Pumphrey. I am currently in the process of developing a radiative transfer model for prediction of tropical longwave emission, and have worked on Andes induced cloud ice by tracing the Jet Stream using EOS MLS measurements.

My PhD involves assessing the affect of ice clouds on the Earth's top-of-atmosphere longwave energy flux.  To achieve this I make use of NASA A-train satellite data from two key satellites; Aura and Aqua, which follow precisely the same orbital path around 705km above the Earth's surface. This is achieved by a process of colocation.

- Current Research -

[Presentation on the Radiative Effects of Tropical Ice]

- PhD Content - Why Study Ice Clouds? -

Ice clouds are one of the most poorly understood entities in climate science. In particular, the formation of ice particulates in clouds, their micro-physical structure (size and shape) is so variable from location to location. A-train data can be used to tackle this problem, since synergistic comparisons can be made between cloud data from different satellite instruments that comprise the same constellation.

- How Does the EOS MLS Instrument Work? -

The MLS instrument is extremely sensitive and is able to detect passive (natural) sources of microwave emission from many radiatively active trace gases on the limb (edge) of the Earth's atmosphere. In order to achieve this, the MLS instrument payload includes both a set of radio-telescopes and GHz and THz frequency detectors (radiance counters). By "mixing" the radiance signal, with a local oscillator of known frequency within a mixer, the difference between the received signal and the detection can be analysed by selection of spectrally isolated double-sideband frequencies. The mathematics of microwave inverse theory used by the MLS team is described in detail by Livesey et al., 2006.

The cloud ice detection functions differently to retrievals of atmospheric gases. An algorithm has been produced by the NASA JPL team that computes a forward model calculation of "expected" clear-sky radiance along the limb using MLS retrievals. If the observed radiant temperature i.e. the perturbation from the clear-sky radiance, often refered to as the cloudy-sky radiance, exceeds a certain threshold, then Ice Water Content (IWC) is computed as a linear regression function proportional to the perturbed signal, based on spherical particles and a suitable particle-size distribution. The algorithm functions well only for tropical cumulonimbus clouds, due to the poor detection of thin midlatitude and anvil outflow cirrus, due to the low signal to noise ratio and the different micro-physical processes and parameterisation schemes required for such detection. The cloud ice algorithm is described by Dong Wu et al., 2006.

My Thesis title is:

"Study into the Radiative and Dynamical
Effects of Ice Clouds Using 
Colocated A-Train
Satellite Observations"

Hobbies ...

squash, climbing, cycling, skiing, weather forecasting

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