Evaluation of OCO-2 X Variability at Local and Synoptic Scales using Lidar and In Situ Observations from the ACT-America Campaigns

An interpolation method is described for range measurements of high precision altimetry with repeating intensity modulated continuous wave (IM-CW) lidar waveforms using binary phase shift keying (BPSK), where the range profile is determined by means of a cross-correlation between the digital form of the transmitted signal and the digitized return signal collected by the lidar receiver. This method uses reordering of the array elements in the frequency domain to convert a repeating synthetic pulse signal to single highly interpolated pulse. This is then enhanced further using Richardson–Lucy deconvolution to greatly enhance the resolution of the pulse. We show the sampling resolution and pulse width can be enhanced by about two orders of magnitude using the signal processing algorithms presented, thus breaking the fundamental resolution limit for BPSK modulation of a particular bandwidth and bit rate. We demonstrate the usefulness of this technique for determining cloud and tree canopy thicknesses far beyond this fundamental limit in a lidar not designed for this purpose.

Super-resolution technique for CW lidar using Fourier transform reordering and Richardson-Lucy deconvolution.

. To check the accuracy of column-average dry air CO2 mole fractions ( XCO2 ) retrieved from Orbiting Carbon Overvatory (OCO-2) data, a similar quantity has been measured from the Multi-functional Fiber Laser Lidar (MFLL) aboard aircraft flying underneath OCO-2 as part of the Atmospheric Carbon and Transport (ACT)-America flight campaigns. Here we do a lagged correlation analysis of these MFLL-OCO-2 column CO2 differences and find that their correlation spectrum falls off rapidly at along-track separation distances of under 10 km, with a correlation length scale of about 10 km, and less rapidly at longer separation distances, with a correlation length scale of about 20 km. The OCO-2 satellite takes many CO2 measurements with small (~3 km2) fields of view (FOVs) in a thin ( The new correlation model gives 10-second XCO2 averages that are only a few tenths of a ppm different from the constant-correlation model. Over land, the uncertainties in the mean are also similar, suggesting that the +0.3 constant correlation coefficient currently used in the model there is accurate. Over the oceans, the twice-the-land correlation lengths that we assume here result in a significantly lower uncertainty on the mean than the +0.6 constant correlation currently gives – measurements similar to the MFLL ones are needed over the oceans to do better. Finally, we show how our 1-D exponential error correlation model may be used to account for correlations in those inversion methods that choose to assimilate each XCO2 retrieval individually, and to account for correlations between separate 10-second averages when these are assimilated instead.

/pdf/a-new-exponentially-decaying-error-correlation-model-3g7ptogqgl.pdf

A new exponentially-decaying error correlation model forassimilating OCO-2 column-average CO 2 data, using a length scalecomputed from airborne lidar measurements

In 2004 ITT Exelis developed the Multifunctional Fiber Laser Lidar (MFLL) for measuring atmospheric CO2. This lidar relies on high efficiency telecom laser components and Erbium Doped Fiber Amplifiers (EDFA’s) to implement a unique Continuous Wave (CW) Intensity Modulated (IM) differential absorption lidar measurement. This same
approach has also been used to measure atmospheric O2 by replacing the EDFA’s with fiber Raman amplifier technology. The use of all fiber coupled components results in a highly reliable, flexible and robust instrument. The general architecture of the MFLL, its implementation for greenhouse gas measurements, and as a pseudorandom noise encoded altimeter system is reviewed. Results from a 2011 flight campaign on the NASA DC-8 aircraft which included CO2, O2, and PN altimetry using a single receiver for all three measurements are also discussed. In addition, an introduction to a novel variation of this approach that will enable greenhouse gas monitoring from a geostationary orbit is given. This paper provides a general overview of a set of applications for fiber lasers in the area of active remote sensing that have been developed by Exelis over the past several years.

Applications of fiber lasers for remote sensing of atmospheric greenhouse gases

A new modulation technique for Continuous Wave (CW) Lidar is presented based on Binary Phase Shift Keying (BPSK) using orthogonal carriers closely spaced in frequency, modulated by Maximum Length (ML) sequences, which have a theoretical autocorrelation function with no sidelobes. This makes it possible to conduct multi-channel atmospheric differential absorption measurements in the presence of thin clouds without the need for further processing to remove errors caused by sidelobe interference while sharing the same modulation bandwidth. Flight tests were performed and data were collected using both BPSK and linear swept frequency modulation. This research shows there is minimal or no sidelobe interference in the presence of thin clouds for BPSK compared to linear swept frequency with significant sidelobe levels. Comparisons between of CO2 optical depth Signal to Noise (SNR) between the BPSK and linear swept frequency cases indicate a 21% drop in SNR for BPSK experimentally using the instrument under consideration.

Binary phase shift keying on orthogonal carriers for multi-channel CO_2 absorption measurements in the presence of thin clouds

A multi-pixel laser altimeter using pseudo-random-noise-modulated fiber lasers has been developed for Climate Change research and Exploration. The architecture supports a wide set of operational parameters (range resolution, range ambiguity interval, temporal update rate) without modifications to the hardware. These parameters can be changed dynamically, based on mission operational needs. The implementation is suitable for orbital and sub-orbital platforms and has reached TRL 6 having flown in a relevant environment over relevant terrain. We will present the status of the instrument development efforts, the results from the on-going field campaign, and notional implementations for Earth Science Decadal Missions and Exploration.

http://www.sensl.com/downloads/irp/2008_Dobbs_FiberLaser_LIDAR_EarthSci.pdf

A Multi-Functional Fiber Laser Lidar for Earth Science & Exploration

Technology advancement for the ASCENDS mission using the ASCENDS CarbonHawk Experiment Simulator (ACES)

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

D. McGregor

Author Tools

Chat about Author

Papers

A Multi-Functional Fiber Laser Lidar for Earth Science & Exploration

Technology advancement for the ASCENDS mission using the ASCENDS CarbonHawk Experiment Simulator (ACES)