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NOAA CREST- CURE Program( Summer Internship 2015)

Example of the learned concepts and part of the research results.

Nelson Ojeda Quiles

on 1 November 2016

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Transcript of NOAA CREST- CURE Program( Summer Internship 2015)

Knowledge is gained by learning; trust by doubt; skill by practice; and science by research.
Nelson Ojeda Quiles
Inversion for Aerosol
Thank YOU For your support and great Opportunity!!!
Structure of the Atmosphere
Meteorology, Climatology and Remote Sensing Applications
Direct relation with improving Remote Sensing Technologies that study the atmosphere.

It is of fundamental importance to our global climate energy budget.
Flux of solar radiation incident on the top of the atmosphere.
Flux(S)- the measure of the strength of electromagnetic radiation incident at a flat surface.
Retrieval method Reference Parameters
Mark area of best aerosol and molecules spectrum signal from a top view perspective
Source: R.P. Loughman :Default MODTRAN profile for tropical atmo, zenith path
Aerosols Retrieval Model Methodology
Convergence after two Chahine Iterations until approximately 0.1% difference
First guess +5% extinction for scattering angle=46.9
Convergence after five Chahine Iterations until approximately 0.0% difference
First guess +60% extinction for scattering angle=46.9

1. First guess input parameter
Extinction change of up to 60% increments
2. Run of Forward Model
3. Use of the Retrieval Method
4. Matlab (Data Analysis tool)
Extinction Profile of Aerosols
% Difference between TrueExt & IteratedExt

Since the launch of the Nimbus-7 satellite in 1978 we have continuously improved our understanding and information of the levels of solar radiation(SR) just before it strikes the Earth’s atmosphere.
Ernest Nyaku and Dr. Robert Loughman
Advisers and other graduate students
Hampton University
Department of Atmospheric and Planetary Sciences
Forward model
sigma (-10%)
mean radius 0.077µm
Sulfuric acid spherical particles
1.44 refrcomplex (no absorption
Extinction :
ozone,nitrogen dioxide
It is possible to retrieve aerosol extinction from limb scattering data at the 756nm wavelength. Regardless of what our first guess is, after performing a sufficient number of Chahine iteration, we can get back to the truth with an accuracy better than 0.2%.

Result Analysis
Redrafted from an illustration by J.T Kiehl and Kevin E. Tensberth
Atmospheric Research
d = 1.5 x10 km
SR ~ 3.9x10 W
S = 1370 Wm

Area = πR
Extinction Coefficient (β)
The measure of how strongly radiation is attenuated by absorption and/or scattering.(Attenuation per unit path length)
How does it work?
Global coverage
High vertical resolution
Scattering Sketch
Extinction percentage change
Important Aerosol Properties
1. Extinction Profile - measure of how much light is attenuated by the scattering along the different atmosphere altitudes.

2. Phase Function (PF) - probability that light/photon will be scattered in a particular direction.
How do we use that data?
Measured radiance is inverted to obtain profiles for constituents such as aerosol, ozone, etc.

1. Compare what the instrument detects to what we can simulate.
How can this be done?
2. By calculating what the instrument sees, as a function of position and viewing direction given the appropriate properties of the atmosphere.
Uses the bright limb to measure the different scattered radiation that enter into it's line of sight (LOS).
Limb Scattering Technique
Pattern of scattering by size difference
Rayleigh Scattering
Mie Scattering
Mie Scattering
larger particles
Direction of incident light
λ >> r
λ < r
λ < r
Synthetic Data Generation
λ= 756nm
First Test
Second Test
1. Extinction
2. Sigma
< 1.50x10
Absolute Difference
Absolute % Difference
< 0.8
Changing size distribution and by consecuence the PF
Using the Chahine Relaxation Method
Mode radius
Aerosol Size Distribution
Standard Deviation
Sigma (σ)
Future WORK
Source: Rault and Loughman, 2013
Retrieval Method
1. First guess input parameter
sigma -10%
2. Run of Forward Model
3. Use of the Retrieval Method
4. Matlab (Data Analysis tool)
Extinction Profile of Aerosols
% Difference between TrueExt & IteratedExt
First guess -10% sigma for scattering angle=46.9
Result Analysis
This test showed the reliability of aerosols retrievals with size distribution changes.
Sigma change
It is possible to retrieve aerosol profiles using the 756nm wavelength.

The retrieval model algorithm works within an accuracy of less then 0.2% using the Chahine Relaxation Method.

Limb scattering technique ability to give accurate size distribution measurements shows key properties in stratospheric aerosols characterization.
Further work with retrievals with noise variations.
Test the behavior of the retrieval algorithm with other scattering angles.
NOAA Office of Educational Partnership Programs
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