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At least 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

The preservation of LANDSAT data by the National Land Remote Sensing Archive

Digital data, acquired by the National Landsat Remote Sensing Program, document nearly two decades of global agricultural, environmental, and sociological change. The data were widely applied and continue to be essential to a variety of geologic, hydrologic, agronomic, and strategic programs and studies by governmental, academic, and commercial researchers. Landsat data were acquired by five observatories that use primarily two digital sensor systems. The Multispectral Scanner (MSS) was onboard all five Landsats, which have orbited over 19 years; the higher resolution Thematic Mapper (TM) sensor acquired data for the last 9 years on Landsats 4 and 5 only. The National Land Remote Sensing Archive preserves the 800,000 scenes, which total more than 60 terabytes of data, on master tapes that are steadily deteriorating. Data are stored at two terabytes of data, on master tapes that are steadily deteriorating. Data are stored at two locations (Sioux Falls, South Dakota and Landover, Maryland), in three archive formats. The U.S. Geological Survey's EROS Data Center has initiated a project to consolidate and convert, over the next 4 years, two of the archive formats from antiquated instrumentation tape to rotary-recorded cassette magnetic tape. The third archive format, consisting of 300,000 scenes of MSS data acquired from 1972 through 1978, will not be converted because of budgetary constraints. This data preservation project augments EDC's experience in data archiving and information management, expertise that is critical to EDC's role as a Distributed Active Archive Center for the Earth Observing System, a new and much larger national earth science program.

Boyd, John E.↗
NASA NTRS1993

Loading and testing a light scattering cell with a binary fluid mixture near its critical composition

Critical phenomena has been the subject of physics research for many years. However, only in recent years has the research effort become intense. The current intensity has caused the study of critical phenomena to be grouped into a previous older era and a present contemporary era. Turbidity cell filling with methanol cyclohexane is one of the first steps toward a further understanding of critical phenomena. Work performed during the research period is outlined. During this period, research was spent developing apparatus and techniques that will make it possible to study critical phenomena through turbidity measurements on methanol cyclohexane. Topics covered range from the orientation of turbidity cell parts for assembly to the filling apparatus and procedure used when th cell is built. The last section will briefly cover some of the observations made when viewing the cell in a controlled water bath. However, before mention is made of the specifics of the summer research, a short introduction to critical phenomena and turbidity and how they relate to this experiment is provided.

Jacobs, Donald T.↗
NASA NTRS1993

Development of methodologies for the estimation of thermal properties associated with aerospace vehicles

Thermal stress analyses are an important aspect in the development of aerospace vehicles such as the National Aero-Space Plane (NASP) and the High-Speed Civil Transport (HSCT) at NASA-LaRC. These analyses require knowledge of the temperature within the structures which consequently necessitates the need for thermal property data. The initial goal of this research effort was to develop a methodology for the estimation of thermal properties of aerospace structural materials at room temperature and to develop a procedure to optimize the estimation process. The estimation procedure was implemented utilizing a general purpose finite element code. In addition, an optimization procedure was developed and implemented to determine critical experimental parameters to optimize the estimation procedure. Finally, preliminary experiments were conducted at the Aircraft Structures Branch (ASB) laboratory.

Scott, Elaine P.↗
NASA NTRS2000

Aerospace Safety Advisory Panel Annual Report for 1999

This report covers the activities of the Aerospace Safety Advisory Panel (ASAP) for the calendar year 1999.This was a year of notable achievements and significant frustrations. Both the Space Shuttle and International Space Station (ISS) programs were delayed.The Space Shuttle prudently postponed launches after the occurrence of a wiring short during ascent of the STS-93 mission. The ISS construction schedule slipped as a result of the Space Shuttle delays and problems the Russians experienced in readying the Service Module and its launch vehicle. Each of these setbacks was dealt with in a constructive way. The STS-93 short circuit led to detailed wiring inspections and repairs on all four orbiters as well as analysis of other key subsystems for similar types of hidden damage. The ISS launch delays afforded time for further testing, training, development, and contingency planning. The safety consciousness of the NASA and contractor workforces, from hands-on labor to top management, continues high. Nevertheless, workforce issues remain among the most serious safety concerns of the Panel. Cutbacks and reorganizations over the past several years have resulted in problems related to workforce size, critical skills, and the extent of on-the-job experience. These problems have the potential to impact safety as the Space Shuttle launch rate increases to meet the demands of the ISS and its other customers. As with last year's report, these work- force-related issues were considered of sufficient import to place them first in the material that follows. Some of the same issues of concern for the Space Shuttle and ISS arose in a review of the launch vehicle for the Terra mission that the Panel was asked by NASA to undertake. Other areas the Panel was requested to assess included the readiness of the Inertial Upper Stage for the deployment of the Chandra X-ray Observatory and the possible safety impact of electromagnetic effects on the Space Shuttle. The findings and recommendations in this report do not highlight any major, immediate issues that might compromise the safe pursuit of the various NASA programs. They do, however, cover concerns that the Panel believes should be addressed in the interest of maintaining NASA's excellent safety record.The Panel is pleased to note that remedial efforts for some of the findings raised are underway. Given appropriate funding and cooperative efforts among the Administration, the Congress and the various contractors, the Panel is convinced that safety problems can be avoided or solved resulting in lower risk for NASA's human space and aeronautics programs. Section II of this report contains specific findings and recommendations generated by Panel activities during the calendar year 1999. Section III presents more detailed information in support of these findings and recommendations. A current roster of Panel members, consultants, and staff is included as Appendix A. Appendix B contains NASA's response to the findings and recommendations from the 1998 annual report. It has been augmented this year to include brief explanations of why the Panel classified the NASA response as " open,""continuing," or "closed." Appendix C lists the fact-finding activities of the Panel in 1999.

Blomberg, Richard D.↗
NASA NTRS2002

Failure Mode Identification Through Clustering Analysis

Research has shown that nearly 80% of the costs and problems are created in product development and that cost and quality are essentially designed into products in the conceptual stage. Currently, failure identification procedures (such as FMEA (Failure Modes and Effects Analysis), FMECA (Failure Modes, Effects and Criticality Analysis) and FTA (Fault Tree Analysis)) and design of experiments are being used for quality control and for the detection of potential failure modes during the detail design stage or post-product launch. Though all of these methods have their own advantages, they do not give information as to what are the predominant failures that a designer should focus on while designing a product. This work uses a functional approach to identify failure modes, which hypothesizes that similarities exist between different failure modes based on the functionality of the product/component. In this paper, a statistical clustering procedure is proposed to retrieve information on the set of predominant failures that a function experiences. The various stages of the methodology are illustrated using a hypothetical design example.

Arunajadai, Srikesh G.↗
NASA NTRS2009

Verification and Validation of Adaptive and Intelligent Systems with Flight Test Results

F-15 IFCS project goals are: a) Demonstrate Control Approaches that can Efficiently Optimize Aircraft Performance in both Normal and Failure Conditions [A] & [B] failures. b) Advance Neural Network-Based Flight Control Technology for New Aerospace Systems Designs with a Pilot in the Loop. Gen II objectives include; a) Implement and Fly a Direct Adaptive Neural Network Based Flight Controller; b) Demonstrate the Ability of the System to Adapt to Simulated System Failures: 1) Suppress Transients Associated with Failure; 2) Re-Establish Sufficient Control and Handling of Vehicle for Safe Recovery. c) Provide Flight Experience for Development of Verification and Validation Processes for Flight Critical Neural Network Software.

Burken, John J.↗
NASA NTRS2009

Shuttle Shortfalls and Lessons Learned for the Sustainment of Human Space Exploration

Much debate and national soul searching has taken place over the value of the Space Shuttle which first flew in 1981 and which is currently scheduled to be retired in 2010. Originally developed post-Saturn Apollo to emphasize affordability and safety, the reusable Space Shuttle instead came to be perceived as economically unsustainable and lacking the technology maturity to assure safe, routine access to low earth orbit (LEO). After the loss of two crews, aboard Challenger and Columbia, followed by the decision to retire the system in 2010, it is critical that this three decades worth of human space flight experience be well understood. Understanding of the past is imperative to further those goals for which the Space Shuttle was a stepping-stone in the advancement of knowledge. There was significant reduction in life cycle costs between the Saturn Apollo and the Space Shuttle. However, the advancement in life cycle cost reduction from Saturn Apollo to the Space Shuttle fell far short of its goal. This paper will explore the reasons for this shortfall. Shortfalls and lessons learned can be categorized as related to design factors, at the architecture, element and sub-system levels, as well as to programmatic factors, in terms of goals, requirements, management and organization. Additionally, no review of the Space Shuttle program and attempt to take away key lessons would be complete without a strategic review. That is, how do national space goals drive future space transportation development strategies? The lessons of the Space Shuttle are invaluable in all respects - technical, as in design, program-wise, as in organizational approach and goal setting, and strategically, within the context of the generational march toward an expanded human presence in space. Beyond lessons though (and the innumerable papers, anecdotes and opinions published on this topic) this paper traces tangible, achievable steps, derived from the Space Shuttle program experience, that must be a part of any 2l century initiatives furthering a growing human presence beyond earth.

Zapata, Edgar↗
NASA NTRS2015

IAF 15 Draft Paper

With the International Space Station Program transition from assembly to utilization, focus has been placed on the optimization of essential resources. This includes resources both resupplied from the ground and also resources produced by the ISS. In an effort to improve the use of two of these, the ISS Engineering teams, led by the ISS Program Systems Engineering and Integration Office, undertook an effort to modify the techniques use to perform several key on-orbit events. The primary purposes of this endeavor was to make the ISS more efficient in the use of the Russian-supplied fuel for the propulsive attitude control system and also to minimize the impacts to available ISS power due to the positioning of the ISS solar arrays. Because the ISS solar arrays are sensitive to several factors that are present when propulsive attitude control is used, they must be operated in a manner to protect them from damage. This results in periods of time where the arrays must be positioned, rather than autonomously tracking the sun, resulting in negative impacts to power generated by the solar arrays and consumed by both the ISS core systems and payload customers. A reduction in the number and extent of the events each year that require the ISS to use propulsive attitude control simultaneously accomplishes both these goals. Each instance where the ISS solar arrays normal sun tracking mode must be interrupted represent a need for some level of powerdown of equipment. As the magnitude of payload power requirements increases, and the efficiency of the ISS solar arrays decreases, these powerdowns caused by array positioning, will likely become more significant and could begin to negatively impact the payload operations. Through efforts such as this, the total number of events each year that require positioning of the arrays to unfavorable positions for power generation, in order to protect them against other constraints, are reduced. Optimization of propulsive events and transitioning some of them to non-propulsive CMG control significantly reduces propellant usage on the ISS leading to the reduction of the propellant delivery requirement. This results in move available upmass that can be used for delivering critical dry cargo, additional water, air, crew supplies and science experiments.

Menkin, Evgeny↗
NASA NTRS2024

Maximizing the Volume of Collocated Data from Two Coordinated Suborbital Platforms

Suborbital (e.g., airborne) campaigns that carry advanced remote sensing and in situ payloads provide detailed observations of atmospheric processes, but can be challenging to use when it is necessary to geographically collocate data from multiple platforms that make repeated observations of a given geographic location at different altitudes. This study reports on a data collocation algorithm that maximizes the volume of collocated data from two coordinated suborbital platforms and demonstrates its value using data from the NASA Aerosol Cloud Meteorology Interactions Over the western Atlantic Experiment (ACTIVATE) suborbital mission. A robust data collocation algorithm is critical for the success of the ACTIVATE mission goal to develop new and improved remote sensing algorithms, and quantify their performance. We demonstrate the value of these collocated data to quantify the performance of a recently developed vertically resolved lidar + polarimeter–derived aerosol particle number concentration (Na ) product, resulting in a range-normalized mean absolute deviation (NMAD) of 9% compared to in situ measurements. We also show that this collocation algorithm increases the volume of collocated ACTIVATE data by 21% compared to using only nearest-neighbor finding algorithms alone. Additional to the benefits demonstrated within this study, the data files and routines produced by this algorithm have solved both the critical collocation and the collocation application steps for researchers who require collocated data for their own studies. This freely available and open-source collocation algorithm can be applied to future suborbital campaigns that, like ACTIVATE, use multiple platforms to conduct coordinated observations, e.g., a remote sensing aircraft together with in situ data collected from suborbital platforms.

Atmosphere↗
NASA NTRS2010

Australian Soil Moisture Field Experiments in Support of Soil Moisture Satellite Observations

Large-scale field campaigns provide the critical fink between our understanding retrieval algorithms developed at the point scale, and algorithms suitable for satellite applications at vastly larger pixel scales. Retrievals of land parameters must deal with the substantial sub-pixel heterogeneity that is present in most regions. This is particularly the case for soil moisture remote sensing, because of the long microwave wavelengths (L-band) that are optimal. Yet, airborne L-band imagers have generally been large, heavy, and required heavy-lift aircraft resources that are expensive and difficult to schedule. Indeed, US soil moisture campaigns, have been constrained by these factors, and European campaigns have used non-imagers due to instrument and aircraft size constraints. Despite these factors, these campaigns established that large-scale soil moisture remote sensing was possible, laying the groundwork for satellite missions. Starting in 2005, a series of airborne field campaigns have been conducted in Australia: to improve our understanding of soil moisture remote sensing at large scales over heterogeneous areas. These field data have been used to test and refine retrieval algorithms for soil moisture satellite missions, and most recently with the launch of the European Space Agency's Soil Moisture Ocean Salinity (SMOS) mission, to provide validation measurements over a multi-pixel area. The campaigns to date have included a preparatory campaign in 2005, two National Airborne Field Experiments (NAFE), (2005 and 2006), two campaigns to the Simpson Desert (2008 and 2009), and one Australian Airborne Cal/val Experiment for SMOS (AACES), just concluded in the austral spring of 2010. The primary airborne sensor for each campaign has been the Polarimetric L-band Microwave Radiometer (PLMR), a 6-beam pushbroom imager that is small enough to be compatible with light aircraft, greatly facilitating the execution of the series of campaigns, and a key to their success. An L-band imaging radar is being added to the complement to provide simultaneous active-passive L-band observations, for algorithm development activities in support of NASA's upcoming Soil Moisture Active Passive (.S"M) mission. This paper will describe the campaigns, their objectives, their datasets, and some of the unique advantages of working with small/light sensors and aircraft. We will also review the main scientific findings, including improvements to the SMOS retrieval algorithm enabled by NAFE observations and the evaluation of the Simpson Desert as a calibration target for L-band satellite missions. Plans for upcoming campaigns will also be discussed.

Kim, Edward↗
NASA NTRS2002

A critical period for functional vestibular development in zebrafish

We have determined a critical period for vestibular development in zebrafish by using a bioreactor designed by NASA to simulate microgravity for cells in culture. A critical period is defined as the briefest period of time during development when stimulus deprivation results in long lasting or permanent sensory deficits. Zebrafish eggs were collected within 3 hours of being laid and fertilized. In experiment 1, eggs were placed in the bioreactor at 3, 24, 30, 36, 48, or 72 hours postfertilization (hPF) and maintained in the bioreactor until 96 hPF. In experiment 2, eggs were placed in the bioreactor immediately after they were collected and maintained in the bioreactor until 24, 36, 48, 60, 66, 72, or 96 hPF. Beginning at 96 hPF, all larvae had their vestibulo-ocular reflexes (VOR) evaluated once each day for 5 days. Only larvae that hatched from eggs that were placed in the bioreactor before 30 hPF in experiment 1 or removed from the bioreactor later than 66 hPF in experiment 2 had VOR deficits that persisted for at least 5 days. These data suggest a critical period for vestibular development in the zebrafish that begins before 30 hPF and ends after 66 hPF. To confirm this, zebrafish eggs were placed in the bioreactor at 24 hPF and removed at 72 hPF. VORs were evaluated in these larvae once each day for 5 days beginning at 96 hPF. These larvae had VOR deficits that persisted for at least 5 days. In addition, larvae that had been maintained in the bioreactor from 24 to 66 hPF or from 30 to 72 hPF, had only temporary VOR deficits. In a final experiment, zebrafish eggs were placed in the bioreactor at 3 hPF and removed at 96 hPF but the bioreactor was turned off from 24 hPF to 72 hPF. These larvae had normal VORs when they were removed from the bioreactor at 96 hPF. Taken as a whole, these data support the idea that there is a critical period for functional maturation of the zebrafish vestibular system. The developmental period identified includes the timeframe during which the vestibular primary afferent neurons are born, innervate their central and peripheral targets, and remodel their central projections. Copyright 2002 Wiley-Liss, Inc.

Non-NASA Center↗
NASA NTRS1999

Results of the First Astronaut-Rover (ASRO) Field Experiment: Lessons and Directions for the Human Exploration of Mars

The first Astronaut-Rover Interaction field experiment (hereafter designated as the ASRO project) took place Feb. 22-27, 1999, in Silver Lake, Mojave Desert, CA. The ASRO project is the result of a joint project between NASA Ames Research Center and Johnson Space Center. In the perspective of the Human Exploration and Development of Space (HEDS) of the Solar System, this interaction - the astronaut and the rover as a complementary and interactive team - in the field is critical to assess but had never been tested before the Silver Lake experiment. Additional information is contained in the original extended abstract.

Cabrol, N. A.↗
NASA NTRSDate not supplied

Preliminary Findings of the Experimental Development Unit Cold Flow Test for a Generation Zero Nuclear Propulsion Engine

Nuclear thermal propulsion (NTP) technology will greatly benefit human travel to Mars by significantly shortening transit times, improving crew safety, and providing more mission flexibility than traditional chemical rockets. As part of DRACO follow-on work to develop, build, and fly a generation zero NTP engine, a full scale flight-like experimental design unit (EDU) reactor was constructed to collect sufficient on-ground performance data to characterize flow induced vibrations (FIV) of critical reactor structures/components, inform development of the engine and reactor control algorithm, and collect pressure drop and flow distribution data across the reactor. The fluid conditions for the test program were designed to achieve system responses equivalent to that of an operational engine through all phases of engine operation including reactor startup, mainstage operation, reactor shutdown, and reactor cooldown. Over 100 tests were executed, flowing either GN2 or GHe through the EDU at varying flow rates and pressures. This experiment provided early validation of flow behavior and vibration risks before nuclear testing, boosted critical subsystem TRLs, informed design iterations, and reduced future test costs. The steady-state flow parameters for the experiment were modeled in Ansys Thermal Desktop, allowing rapid tuning and experiment-informed updates to a flight-like test matrix. The EDU dynamic environment was characterized with accelerometers, strain gauges, and high-frequency pressure transducers all sampled at 20 kHz. While many narrow-band oscillations were identified, no significant FIV occurred; the reactor structural responses tend to be enveloped by typical launch vehicle ascent vibration environments (defined up to 2 kHz), although significant energy is also present at higher frequencies.

Flow Induced Vibration↗
NASA NTRS1985

Convective influence on the stability of a cylindrical solid-liquid interface

Experiments in which a long vertical, heated wire is surrounded by concentric annuli of a melt and its crystalline solid show that the convection state changes from a stable unicell surrounded by a stationary cylindrical solid-liquid interface, to a complex time-dependent flow surrounded by a rotating, helical solid-liquid interface. This transition occurs at a Grashof number of approximately 150, which is an order of magnitude less than the critical Grashof number calculated for a liquid annulus surrounded by rigid walls. A linear stability analysis has been carried out for an infinitely tall vertical annulus. When the deformable nature of the crystal-melt interface is taken into account in the boundary conditions, two new modes of instability arise. The most dangerous mode is asymmetrical and corresponds to helical waves travelling vertically upwards. The critical Grashof number and the scaling properties of the eigenstate agree with experiments. The results clearly demonstrate the coupling of convection with crystal-melt interfacial instabilities.

Fang, Q. T.↗
NASA NTRS2003

Cellular Instabilities and Self-Acceleration of Expanding Spherical Flames

In the present investigation we aim to provide experimental information on and thereby understanding of the generation and propagation of spark-ignited, outwardly propagating cellular flames, with three major focuses. The first is to unambiguously demonstrate the influence of the four most important parameters in inducing hydrodynamic and diffusional-thermal cellularities, namely thermal expansion, flame thickness, non-unity Lewis number, and global activation energy. The second is to investigate the critical state for the onset of cellularity for the stretch-affected, expanding flame. The third is to identify and consequently quantify the phenomena of self-acceleration and possibly auto-turbulization of cellular flames. Due to space limitation the effects of activation energy and the critical state for the onset of cellularity will not be discussed herein. Experiments were conducted using C3H8-air and H2-O2-N2 mixtures for their opposite influences of non-equidiffusivity. The additional system parameters varied were the chamber pressure (p) and the mixture composition including the equivalence ratio (phi). From a sequence of the flame images we can assess the propensity of cell formation, and determine the instantaneous flame radius (R), the flame propagation rate, the global stretch rate experienced by the flame, the critical flame radius at which cells start to grow, and the average cell size.

Law, C. K.↗
NASA NTRS1996

A Fundamental Study of Laser Beam Welding Aluminum-Lithium Alloy 2195 for Cryogenic Tank Applications

Based on the potential for decreasing costs of joining stiffeners to skin by laser beam welding, a fundamental research program was conducted to address the impediments identified during an initial study involving laser beam welding of aluminum-lithium alloys. Initial objectives of the program were the identification of governing mechanism responsible for process related porosity while establishing a multivariant relationship between process parameters and fusion zone geometry for laser beam welds of alloy 2195. A three-level fractional factorial experiment was conducted to establish quantitative relationships between primary laser beam processing parameters and critical weld attributes. Although process consistency appeared high for welds produced during partial completion of this study, numerous cracks on the top-surface of the welds were discovered during visual inspection and necessitated additional investigations concerning weld cracking. Two experiments were conducted to assess the effect of filler alloy additions on crack sensitivity: the first experiment was used to ascertain the effects of various filler alloys on cracking and the second experiment involved modification to process parameters for increasing filler metal dilution. Results indicated that filler alloys 4047 and 4145 showed promise for eliminating cracking.

Martukanitz, R. P.↗
NASA NTRS2004

Exploring PV on the Red Planet: Mars Array Technology Experiment and Dust Accumulation and Removal Technology

The environment on the surface of Mars is different in several critical ways from the orbital environment in which space solar arrays normally operate. Some important differences are: 1) Low intensity, low temperature operation; 2) Spectrum modified by atmospheric dust, varies with time; 3) Indirect sunlight; 4) Possibility of dust atoms at some times of year; 5) Deposited dust; 6) Wind; 7) Peroxide-rich reactive soil. We are developing two experiments to test operation of solar arrays on the surface of Mars, to be flown on the 2001 Surveyor Lander mission. The Mars Array Technology Experiment (MATE) will test the operation of several types of solar cells under Mars conditions, and determine the direct and scattered solar spectrum at the surface. The Dust Accumulation and Removal Technology (DART) experiment will monitor the amount of dust deposition on a target solar cell, measure the characteristics of the dust, and test the feasibility of dust removal.

Landis, Geoffrey A.↗
NASA NTRS2023

Wind Profiling With the Airborne Doppler Aerosol Wind Lidar During the 2022 Convective Processes Experiment

The 2017 Decadal Survey for Earth Science and Applications from Space (ESAS 2017) identifies a critical need for improving our understanding of Planetary Boundary Layer (PBL) processes and air-surface fluxes as well as why clouds, convection, and heavy precipitation occur when and where they do. Lidars are uniquely capable of collecting high precision and high spatio-temporal observations that have been used for atmospheric process studies from the ground, aircraft, and space. The wind lidar team at the NASA Langley Research Center (LaRC) started the development of Doppler wind lidar more than a decade ago to demonstrate technologies required for an Earth-orbiting system to globally measure wind profiles. Since then, an airborne Doppler Aerosol WiNd (DAWN) lidar system has been developed and participated in a series of field campaigns. The Doppler Aerosol WiNd (DAWN) lidar uses atmospheric aerosol motion to derive vertical profiles of horizontal wind speed and direction beneath the aircraft. In September 2022, DAWN, along with a suite of other instruments, was flown on a NASA DC-8 as part of The Convective Processes EXperiment – Cabo Verde (CPEX-CV) field campaign. A main objective of CPEX was to obtain a comprehensive set of temperature, humidity and, particularly, wind observations over tropical waters in undisturbed conditions, Saharan dust outbreaks, and in the vicinity of scattered through organized deep convection in all phases of the convective life cycle. DAWN collected data for approximately 90 hours across 13 CPEX-CV science flights. Airborne Vertical Atmospheric Profiling System (AVAPS) dropsondes were dropped throughout the flight for profiling the atmosphere and validating the DAWN instrument. DAWN had co-located data with 347 AVAPS NRD41 dropsondes, providing 32,117 vertical levels for a comprehensive validation of DAWN wind retrievals. DAWN showed very good agreement with dropsondes of ~0.2 m/s bias and ~1.8 m/s RMS. Given this agreement, DAWN is considered to be a worthy reference dataset, and its retrievals have been compared to winds derived from GOES Atmospheric Motion Vectors (AMVs), Advanced Scatterometer winds (ASCAT), and model data from GFS, GEOS, and MERRA-2 to better understand the quality of our current models and satellite wind observations. The proposed presentation will provide a brief description of the DAWN instrument, discuss the synergistic observations collected across a wide range of atmospheric conditions sampled during the CPEX-CV flights, and a summary of comparisons between DAWN, GOES AMV, ASCAT, and model analyses/predictions, with an emphasis on the PBL.

DAWN↗