Airborne Visible Infrared Imaging Spectrometer (AVIRIS) Datacube of Sullivan’s Island Obtained on October 26, 1998 Color-infrared color composite on top of the datacube was created using three of the 224 bands at 10 nm nominal bandwidth. 1m = 10 6 m = 10 10 nm
Image processing
Aerosol size determination from space True Color False Color Visible Near-infrared Fine particles from smoke Coarse dust particles
Generalized Spectral Reflectance Envelopes for Deciduous and Coniferous Trees
Vegetation reflection Spectral dependence Nice indicator for vegetation: Normalized Difference Vegetation Index (NDVI) NDVI = R NIR − R VIS R NIR + R VIS
Typical Spectral Reflectance Curves for Vegetation, Soil, and Water
Vegetation Spectral Properties: NDVI = R NIR − R VIS R NIR + R VIS
Radiation measurements from the ground In preparation for our experimental measurement’s day we will focus on SunPhotometers and Sky Radiometers In particular the NASA AERONET system: https://aeronet.gsfc.nasa.gov/
https://youtu.be/i_CJW3JsBI4
Forward model: Retrieval scheme: -Spectral and angular scattering by particles with different sizes, compositions and shapes - Accounting for multiple scattering in atmosphere (Dubovik and King, JGR, 2000) Numerical inversion: -Accounting for noise Observations -Solving Ill-posed problem - Setting a priori constraints • Direct solar • Almucantar • Principal Plane Scan aerosol particle sizes, refractive index, single scattering albedo, etc.
Retireved size distribution 0.25 Size Fitting as a retrieval 0.2 Refractive Indices Distribution m 3 / m 2 ) strategy 0.15 0.10 Imaginary Part Imarinary Part 0.1 0.01 Almucantar Fitting 0.05 0 0. 1 10 0.5 Radius (microns) 0.00 1000 0.44 0.67 0.87 1.02 m) Wavelength ( Measurements Int (0.44) * 1000 1.60 0.4 Fitting 100 Real Part Intensity Optical thickness 1.55 Int (0.67) * 100 0.3 1.50 AOD 10 1.45 Int (0.87) * 10 0.2 1 1.40 1.35 0.1 Int (1.02) 0.1 0.44 0.67 0.87 1.02 m) Wavelength ( 0.01 0 0 20 40 60 80 100 120 140 0.40 0.60 0.80 1.0 Scattering Angle (degree) Wavelenths (micron)
The averaged optical properties of various aerosol types (Dubovik et al., 2002, JAS)
Utilizing polarization Cape Verde aerosol Principal Plane: Polarization : t ( l ), I( l,Q ) t ( l ), I( l,Q ),P( l,Q ) l = 0.44, 0.5, 0.67, 0.87,1.02, 1.64, m l = 0.87 m n( l) w 0 ( l) dV/dln(r i ) almucantar principal plane (radiances) almucantar almucantar principal plane (polarization, 0.87 m) principle plane 0.87 m(with polarization) principle plane 0.87 m(with polarization) 1.65 principal plane (4 channels + polar) principle plane (4 channels + polarization) principle plane (4 channels + polarization) 0.14 1 1.6 0.12 Real Part of Reffactive Index Single Scattering Albedo 1.55 0.9 0.1 2 ) 1.5 3 / m 0.08 m 0.8 1.45 dV/dlnR ( 0.06 1.4 0.7 0.04 1.35 0.02 1.3 0.6 0.4 0.5 0.6 0.7 0.8 0.9 1 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 0 0.1 1 10 m) m) Wavelengths ( Wavelengths ( Particle Radius (micron) 28:09: 2003,18:07:54,Principal_Plane,Capo_Verde,47 28:09: 2003,18:07:54,Principal_Plane,Capo_Verde,47 28:09: 2003,18:07:54,Principal_Plane,Capo_Verde,47
Fitting polarization Cape Verde aerosol Radiance Linear Polarizartion 10 0.6 Measurements Measurements Fitting 0.5 Fitting Radiance in Principle Plane 11 ) 12 /F 1 0.4 Linear Polarization (-F 0.3 0.1 0.2 0.1 0.01 0 0 30 60 90 120 150 50 75 100 125 150 Scattering Anlge (degrees) Scattering Anlge (degrees)
Fine and Coarse modes separations total Beijing aerosol 100 fine mode coarse mode Phase Function 10 0.14 1 Beijing Aerosol 0.12 Radiance 0.1 0.1 2 ) 3 / m 0.45 m 0 45 90 135 180 Particle Radius (micron) 0.08 m 02:05: 2003,09:27:51,PolarPP,Beijing,14 dV/dlnR ( 0.06 Coarse Coarse 0.04 Fine total fine mode 0.02 coarse mode 0.9 0 11 ) 0.1 1 10 12 /F Particle Radius (micron) 0.6 Linear Polarization (-F 02:05: 2003,09:27:51,PolarPP,Beijing,14 0.3 Flexible separation between fine and coarse modes 0 (curently: ~0.6 m) 0 45 90 135 180 Particle Radius (micron) 02:05: 2003,09:27:51,PolarPP,Beijing,14
Retrieval using combinations of up-looking Ground-based and down-looking satellite observations Retrieved: Aerosol Properties: - size distribution - real ref. ind. - imag. ref. ind (AERONET sky channels) Surface Parameters: - BRDF (MISR channels) - Albedo (MODIS IR channels)
Polarized Components Total Radiation Phase Function diagram for Rayleigh scattering
Observing geometry from Space: Solar zenith angle Sensor zenith angle Sensor view angle Solar view angle
Field Measurement’s Day Prof. J. Vanderlei Martins Earth and Space Institute – UMBC University of Maryland Baltimore County
Our Experimental Measurement’s day: • Field trip to the MAC (Contemporaneous Art Museum) • Measurements from the roof top of the building observing solar and sky radiances with a simple manual photometer from your smart phone. • The intent is to illustrate how to make measurements and convert it to scientific variables but it is not to actually perform a fully calibrated scientific measurement • First you will characterize and understand better the sensors in your Smart Phone: • Photometer • Camera • Inclinometers, accelerometers, compass, GPS, etc. • Second you will perform actual atmospheric measurements and compare results with AERONET
Ibirapuera Park Across the Street from MAC
What to bring: • We plan to use personal Smart phones for the measurement • Students will be divided in teams of 3 people • Important to have at least one smartphone per team • Not required but very useful to have a laptop computer for data analysis (plotting, etc.). • Sunscreen, hat, long sleeves for wind and sun blocking • Water bottle or mug. • Lunch boxes will be provided by the School.
Important notes: • The museum is a safe/secure place but, keep in mind that you are bringing smartphones, laptops and other belongings at your own risk. • You can visit the whole museum but our experimental activities will happen only the 1 st and 8 th floors. Important: You are not allowed to bring backpacks to any other floors!!! In fact, it is better to keep your backpacks in the 1 st floor rooms dedicated to our group. • Across the street from the museum there is the beautiful Ibirapuera Park that you should consider visiting. While in the Park be always careful with your belongings (computer, cameras, phones, etc.).
Apps to download to your computer: • There are three Apps that we plan to use in this experiment: • Physics toolbox suite • GPS Status • Photometer PRO – Lux Light Meter & Tools Note: Aple Iphone’s will have a different photometer App but it should work similarly If your phone is limited in memory space, start with the Photometer Pro – Lux Light Meter. You may be able to use this App only for all measurements.
Division in groups • Students will be divided in teams of 3 people • There must be at least one smartphone per team. • It would be useful if each team had at least one laptop computer for data analysis. • The student teams will be split into 4 groups lead by a professor and monitors. • The Professors will coordinate the groups to perform experimental activities in the laboratories and on the roof of the museum. • Each group will have an assigned 2 hours window to perform the laboratory characterization of their phone.
Computer and Data analysis • A laptop computer is not required for participation in the course but it is highly recommended. • We will have data analysis and measurement activities for which the laptop computer will be highly beneficial. The work will be done in groups of 3 students so, it is highly advisable to have at least one computer in each group.
Software requirements • Any data analysis software (including excel) can be used to the general data analysis but we will be basin all our measurements and data analysis on Python. • I highly recommend everybody to install and get some familiarity with Python. In particular, I recommend Python 2.7 in the Anaconda distribution.
Poster Session • Student teams will prepare a poster with results from their experiment to present to the whole group of students. We will have a poster session in the last Thursday of the event.
Ext xtra sli lides
‘ s Image Gallery Oct 25th for ACEPOL Oct 23rd (Level 1 data under processing) Oct 19th Oct 26th Nov 1st Oct 27th Nov 9th Nov 9th Nov 3rd Nov 7th
UMBC AirHARP and AirSPEX from ER2 NASA ACEPOL – Nov 2018
HARP cloud retrievals can be done for any pixel in the LMOS FOV, even for heterogeneous clouds , like this case (left) from LMOS on June 19, 2017. Polarized radiance is converted to reflectance ( Rp ) and parametrically matched to Mie phase functions: 𝑆 𝑄 = 𝜌 𝑅 2 + 𝑉 2 12 𝜘 + 𝛾𝑑𝑝𝑡 2 𝜄 + 𝛿 = 𝛽 𝑄 Intensity Polarization 𝐺 0 cos 𝜘 𝑨 AirHARP 670nm Evaluating this relationship on 10x10 super-pixel retrieval (80m total grd. res.) the solar principal plane gives the effective radius (r eff ) and Retrieved Parameters variance (v eff ) of a cloud scene R eff = 6.0um from the recovered Mie P 12 . V eff = 0.03 Level 2 retrieval algorithms and adaptation of HARP data to GRASP for aerosol retrieval AirHARP R P • Best Parametric Fit - - - are underway.
HARP Pioneering Hyper-Angular Capability from Space will Provide Full Cloudbow Retrievals from Small Area (~4x4km) Intensity Polarization 98
HARP CubeSat Polarimeter HARP Pioneering Hyper-Angular Capability will Provide Full Cloudbow Retrievals from Small Area (< 4x4km from space) Water Droplet Distribution Intensity Reff = 20 m Veff = 0.01 D and A produce cloud droplet effective radius Effective Radius ( m) and variance Reff = 20 m Polarization A Veff = 0.09 D These two cases are undistinguishable from Intensity measurements only (MODIS/VIIRS)
HyperAngular High 1 km Resolution Cloudbow Stokes parameters DoLP Cloudy pieces Cloud Hole Scattering Angle Intensity
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