Haris Riris

National Aeronautics and Space Administration · Earth Sciences Division

The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs), beginning in 2004, from over 30 current or past measurement sites around the world using solar absorption spectroscopy in the near-infrared (near-IR) region. TCCON GHG data have been used extensively for multiple purposes, in...

We measured the column-averaged atmospheric CO2 mixing ratio (XCO2) to a variety of cloud tops with an airborne pulsed multi-wavelength integrated path differential absorption (IPDA) lidar during NASA's 2017 ASCENDS/ABoVE airborne campaign. Measurements of height-resolved atmospheric backscatter profiles allow this lidar to retrieve XCO2 to cloud t...

We measured the column-averaged atmospheric CO2 mixing ratio (XCO2) to a variety of cloud tops with an airborne pulsed multi-wavelength integrated path differential absorption (IPDA) lidar during NASA’s 2017 ASCENDS/ABoVE field campaign. Measurements of height- resolved atmospheric backscatter profiles allow this lidar technique to estimate XCO2 to...

The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs) beginning in 2004 from over 30 current or past measurement sites around the world, using solar absorption spectroscopy in the near infrared region. TCCON GHG data have been used extensively for multiple purposes, including in...

Plain Language Summary Wildfires are a major source of greenhouse gases. However, there are large uncertainties in the estimated CO2 emissions from wildfires in global emissions inventories. The estimates of column‐averaged CO2 (XCO2) from satellite measurements using passive remote sensing techniques are significantly degraded or screened out by t...

Wind is the process that connects Mars' climate system. Measurements of Mars atmospheric winds from orbit would dramatically advance our understanding of Mars and help prepare for human exploration of the Red Planet. Multiple instrument candidates are in development and will be ready for flight in the next decade. We urge the Decadal Survey to make...

The present knowledge of the Mars atmosphere is greatly limited by a lack of global measurements of winds and aerosols. Hence, measurements of height-resolved wind and aerosol profiles are a priority for new Mars orbiting missions. We have designed a direct-detection lidar (MARLI) to provide global measurements of dust, winds and water ice profiles...

Remote sensing of methane fluxes has been highlighted as one of the measurement goals of the NASA 2017 Earth Science Decadal Survey. Measuring methane from space and airborne platforms with an active (laser) remote sensing instrument presents several technology and measurement challenges that need to be met in order to provide accurate and precise...

We report on the fabrication and characterization of Er:YGG films suitable for waveguide amplifiers that could in principle be used in integrated path differential absorption lidar systems. Presented is our fabrication technique, comprising pulsed-laser-deposition growth of ~10 μm-thick crystalline films, their channeling via ultraprecision ductile...

This is the second Special Issue on Space Optics of the CEAS Space Journal, 2 years after the first. As in the first Special Issue, the collected papers are largely based on contributions presented at the last International Conference on Space Optics ICSO held in October 2018 in Chania, Greece. ICSO is the largest multi disciplinary meeting of expe...

Here we report on measurements made with an improved CO2 Sounder lidar during the ASCENDS 2014 and 2016 airborne campaigns. The changes made to the 2011 version of the lidar included incorporating a rapidly wavelength-tunable, step-locked seed laser in the transmitter, using a much more sensitive HgCdTe APD detector and using an analog digitizer wi...

We present a neural network algorithm for spectroscopic retrievals of concentrations of trace gases. Using synthetic data we demonstrate that a neural network is well suited for filtering etalon fringes and provides superior performance to conventional least squares minimization techniques. This novel method can improve the accuracy of atmospheric...

We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multi-wavelength integrated-path differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up to 13 km during the 2011, 2013 and 2014 NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (A...

We report on an airborne demonstration of atmospheric oxygen (O2) optical depth measurements with an Integrated Path Differential Absorption (IPDA) lidar using a fiber-based laser transmitter and photon counting detectors. Accurate atmospheric temperature and pressure measurements are needed for NASA’s Active Sensing of CO2 Emissions over Nights, D...

Engineering the optical properties of waveguides is important for the optimization of their guided optical mode characteristics. Here, we document the dynamic control of the refractive index and composition of crystalline films, via the substrate temperature, during pulsed-laser-deposition growth of Er(1%)-doped yttrium gallium garnet on <100>-orie...

Here we report on measurements made with an improved CO2 Sounder lidar during the ASCENDS 2014 and 2016 airborne campaigns. The improvements made to the 2011 version of the lidar instrument included incorporating a rapidly wavelength tunable, step-locked seed laser in the transmitter, using a much more sensitive HgCdTe APD detector, and using an an...

We report on an airborne demonstration of atmospheric methane (CH4) measurements with an integrated path differential absorption lidar using an optical parametric amplifier and optical parametric oscillator laser transmitter and sensitive avalanche photodiode detector. The lidar measures the atmospheric CH4 absorption at multiple, discrete waveleng...

We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multiple wavelengths integrated-path, differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up to 13 km during the 2011, 2013 and 2014 ASCENDS science campaigns flown in the west and mid-west United S...

Increases in atmospheric CO2 and CH4 result from a combination of forcing from anthropogenic emissions and Earth System feedbacks that reduce or amplify the effects of those emissions on atmospheric concentrations. Despite decades of research carbon-climate feedbacks remain poorly quantified. The impact of these uncertainties on future climate are...

Atmospheric methane is the second most important greenhouse gas with 25 times the radiative forcing of carbon dioxide. We will present results from an airborne campaign using a lidar at 1.65µm using optical parametric generation.

We have advanced the science of space-based laser measurements using the spectral purity and frequency tuning of a fiber-amplified lasers performing active remote sensing of atmospheric CO2 column abundance and dry mixing ratio.

The advent of several key enabling electro-optics technologies afford advanced, non-topographic remote sensing instruments for space. We will present progress on several new, space-based laser instruments that are being developed at NASA GSFC. Article not available.

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas, with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. Yet, lack of understanding of the processes that control CH4 sources and sinks and its potential release from stored carbon reservoirs contributes significant uncertainty to our...

An orbiting laser remote sensing instrument (lidar) capable of measuring trace gases on global scales with unprecedented accuracy and high spatial resolution can provide valuable measurements for planetary and earth science missions.

We report on our development effort for a trace-gas-sensing lidar transmitter to be used in future Earth-orbiting satellites. Our lidar transmitter is based on an optical parametric oscillator (OPO), whose output wavelength is switched at a rate of 5 kHz across the target line. The OPO cavity length and the seed laser wavelengths are stabilized to...

We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The lidar measures the atmospheric backscatter profiles and samples the shape of the 1,572.33 nm CO2 absorption line. We participated in the ASCENDS science flights on the NASA DC-8 aircraft during August 2011 and r...

NASA Goddard is developing an integrated-path, differential absorption (IPDA) lidar approach to measure atmospheric CO2 concentrations from space as a candidate for NASA’s ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission. The approach uses pulsed lasers to measure both CO2 and O2 absorption simultaneously in the vert...

We have developed a pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA’s ASCENDS mission. The CO2 lidar flies on NASA’s DC-8 aircraft and measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line using 250 mW average laser power, 30 wavelength sa...

We report on an airborne demonstration of atmospheric oxygen optical depth measurements with an IPDA lidar using a fiber-based laser system and a photon counting detector. Accurate knowledge of atmospheric temperature and pressure is required for NASA’s Active Sensing of CO 2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission, and cli...

We use an airborne pulsed integrated path differential absorption lidar to make spectroscopic measurements of the pressure-induced line broadening and line center shift of atmospheric CO2 at the 1572.335 nm absorption line. We measure the absorption lineshape in the vertical column between the aircraft and ground. A comparison of our measured absor...

We report on airborne CO 2 column absorption measurements made in 2009 with a pulsed direct-detection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United Sta...

Laser instruments designed to measure methane from air- and space-borne platforms are being developed at DLR (MERLIN) and at NASA (GSFC Methane Sounder). Designing these instrument with sufficient accuracy to advance our understanding of emission source strengths and locations is crucial. Here we present a model simulation of methane used to test t...

We report airborne measurements of the column abundance of atmospheric methane made over an altitude range of 3–11 km using a direct detection integrated-path differential-absorption lidar with a pulsed laser emitting at 1651 nm. The laser transmitter was a tunable, seeded optical parametric amplifier pumped by a Nd:YAG laser, and the receiver used...

We are studying an atmospheric lidar for Mars orbit that can continuously measure atmospheric backscatter and depolarization profiles, wind (Doppler shift) profiles and a column gas measurement that directly address high-priority needs for Mars.

We demonstrate the airborne measurement of atmospheric methane using a pulsed lidar at 1650 nm using an integrated path differential absorption scheme. Our seeded nanosecond-pulsed optical parametric amplifier (OPA)-based instrument works up to the highest altitudes flown (> 10 km). Our airborne measurements are in good agreement with the expected...

We report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OPA output has ˜500 MHz linewidth and is widely tunable at both near-infrared and mid-infrared wavelengths, with an optical-optical conversion efficiency of up to ˜39%. Using this laser source, we d...

We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's planned ASCENDS space mission. We have developed an airborne lidar to demonstrate the measurements from aircraft. In 2010 and 2011we measured atmospheric CO2 and O2 column absorptions and line shapes on a series of flights at altit...

We describe a Mars orbital atmospheric lidar that continuously measures vertically resolved atmospheric backscatter profiles, depolarization profiles, wind profiles and column water vapor and that addresses important science needs and knowledge gaps.

NASA is currently developing several Earth science laser missions that were recommended by the US National Research Council (NRC) Earth Science Decadal Report. The Ice Cloud and Land Elevation Satellite-2 (ICESat-2) will carry the Advanced Topographic Laser Altimeter System (ATLAS) is scheduled for launch in 2016. The Active Sensing of CO2 Emission...

A high efficiency, narrow linewidth tunable laser source is developed for greenhouse trace gas remote sensing. It features broad, continuous tuning range at 1570–1655 nm and 3291 nm with narrow linewidth (500 MHz) and high spectral purity. This laser is based on seeded optical parametric generator (OPG) technology. Several trace gas species were co...

We present current and near-term uses of high-power fiber lasers and amplifiers for NASA science and spacecraft applications. Fiber lasers and amplifiers offer numerous advantages for the deployment of instruments on exploration and science remote sensing satellites. Ground-based and airborne systems provide an evolutionary path to space and a mean...

We report on the atmospheric pressure measurements using a fiber-based laser system using the oxygen A-band at 765 nm. Remote measurements of atmospheric temperature and pressure are required for a number of scientific applications including greenhouse gas monitoring, weather prediction, and climate modeling.

We have developed a laser technique for the remote measurement of the tropospheric CO₂ concentrations from space. Our goal is to develop a space instrument and mission approach for active CO₂ measurements.

We report on ground and airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). The technique has been used to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a...

We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-ban...

At NASA's Goddard Space Flight Center we are developing next generation laser transmitters for future spaceflight, remote instruments including a micropulse altimeter for ice-sheet and sea ice monitoring, laser spectroscopic measurements of atmospheric CO2 and an imaging lidar for high resolution mapping of the Earth's surface. These laser transmit...

At NASA's Goddard Space Flight Center, we are developing the next generation laser transmitters for future remote sensing applications including a micropulse altimeter for ice-sheet monitoring, laser spectroscopic measurements and high resolution mapping of the Earth's surface as well as potential missions to other planets for trace gas measurement...

Trace gases in planetary atmospheres offer important clues as to the origins of the planet's hydrology, geology, atmosphere, and potential for biology. We report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OPA output light is single frequency with high...

We present preliminary results in the development of a miniaturized gas correlation radiometer that implements a hollow-core optical fiber (hollow-waveguide) gas correlation cell. The substantial reduction in mass and volume of the gas correlation cell makes this technology appropriate for an orbital mission—capable of pinpointing sources of trace...

Many fundamental questions about planetary evolution require monitoring of the planet's atmosphere with unprecedented accuracy at both high and low latitudes, over both day and night and all seasons. Each planetary atmosphere presents its own unique challenges. For the planets/moons that have relatively low surface pressure and low trace gas concen...

We present a comparison of observations from an airborne pulsed lidar taken during a GOSAT satellite overpass. This was part of the Active Sensing of CO2 Emissions over nights Days and Seasons (ASCENDS) 2010 campaign onboard the NASA DC-8 aircraft. The NASA Goddard pulse lidar system steps a pulsed wavelength-tunable laser transmitter across the 15...

Trace gases and their isotopic ratios in planetary atmospheres offer important but subtle clues as to the origins of a planet's atmosphere, hydrology, geology, and potential for biology. An orbiting laser remote sensing instrument is capable of measuring trace gases on a global scale with unprecedented accuracy, and higher spatial resolution that c...

We have developed a lidar technique for measuring atmospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. It uses pulsed laser transmitters to simultaneously measure a CO2 absorption line in the 1570 nm band, O2 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of...

We report the signal and noise analysis of our recent airborne experiments of CO2 and O2 column concentration measurements with an integrated path differential absorption (IPDA) lidar developed for NASA's Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS) mission. The O2 column absorption measurement is used to derive the atmos...

NASA launched science flight campaigns in summers 2009 and 2010 for future space mission ASCENDS (the Active Sensing of CO2 Emissions over Nights, Days and Seasons). Three NASA laser approaches currently under development in the Goddard Space Flight Center (GSFC), the Langley Research Center and the Jet Propulsion Laboratory flew and tested during...

We report on airborne atmospheric pressure measurements using new fiber-based laser technology and the oxygen A-band at 765 nm. Remote measurements of atmospheric temperature and pressure are required for a number of NASA Earth science missions and specifically for the Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission...

Trace gases and their isotopic ratios in planetary atmospheres offer important but subtle clues as to the origins of a planet's atmosphere, hydrology, geology, and potential for biology. Calculations show that an orbiting laser remote sensing instrument is capable of measuring trace gases on a global scale with unprecedented accuracy, and higher sp...