Vincent B. Wickwar - US grants

There is a dearth of measurements on the dynamics and chemistry of the mesosphere and lower thermosphere, which are the regions in the 70 to 120Km altitude range, because the region is too low for satellites and too high for balloons. The region is closely coupled to the stratosphere below and the upper thermosphere above, and is strongly affected by tides and waves propagating up from the lower atmosphere, and particle precipitation and electric currents originating in the magnetosphere. An opportunity to obtain measurements of the winds, waves and temperature structure of this region has arisen, using an advanced optical interferometer on loan from the University College London, to be set up at a mountain site in Utah. The measurement will be supported by global numerical modelling activities in the USA and UK.

This award is for the use of the Hardware Ranch Observatory (HRO). The facility will be used to test optical and radio instruments and to conduct observing campaigns. This facility will provide a unique opportunity for the NSF community at minimal cost. This award will almost exclusively be committed to operating the Observatory: installing instruments, coordination and making observations, reducing data, making data available to the CEDAR community, and conducting an active research program.

Utah State University will conduct CEDAR research at the Hardware Ranch Observatory (HRO), mid-latitude facility for the study of the upper atmosphere. HRO consists of two sites -- Hardware Ranch and Bear Lake -- that are located in the Wasatch Mountain Range 25 and 38 miles, respectively from the university. Both sites are well situated for optical and radio observations and are very accessible to researchers and students.***//

This award provides funds for continuing support for developing and operating a first-class, imaging Fabry-Perot interferometer. The major research thrust for this IFPI is to study the dynamics and temperatures of the midlatitude mesopause region. A secondary research thrust is to contribute to several global programs involving thermospheric dynamics that are supported by CEDAR and STEP and to participate in specific local research programs. The observations will be made at Utah State University's Bear Lake Observatory.***//

A lidar system developed at the University of Maryland is being restored to operation at Utah State University, as part of the Bear Lake Observatory (BLO) facilities - a mid-latitude CEDAR observatory. Lidar observations will be made initially in the altitude range 30-70 km, as done previously at College Park, covering the upper stratosphere and lower mesosphere. The altitude coverage will be extended with the addition of a more powerful laser by Clemson University upward to 80 km. At higher altitudes, near the mesopause, these lidar observations will be complemented by the passive optical instruments at BLO. Vertical profiles of molecular density and temperature will be derived from clear-air portions of the atmosphere above 30 km, using Rayleigh scattering at 532 nm. The downward extension of these profiles into regions were Mie (particulate) scattering significantly adds to the lidar return will employ Raman scattering from atmospheric molecules. These profiles will be used to examine the occurrence, structure, interaction, and variability of planetary waves, tides, and gravity waves in the middle atmosphere above an extended mountainous region. This award provides funds for the PI to help make the system operational at BLO, and begin measurements.

Application of the coded long-pulse technique to studies of thermal balance in the ionosphere This project is a collaborative effort involving Geospace Research Inc. and Utah State University. The research plan has two components including radar observations of the ionosphere and an assoicated modeling effort. Incoherent scatter of radar waves produces two distinct signals: an ion line and a plasma line. Usually, radar experiments are performed using either one or the other, but a new technique partly developed by Geospace Research Inc. allows both ion line and plasma line to be measured simultaneously. The radar experiments are to be performed at Arecibo in Puerto Rico and with the EISCAT facility in Europe. The resulting data provides a comprehensive set of measurements of the density and thermal properties of the ionospheric plasma. When combined with modeling, the measurements will be used to study a number of different processes that affect the observed behavior of the ionosphere.

A lidar consortium consisting of Clemson University (CU), Utah State University (USU), the University of Maryland (UMD), and the University of Pittsburgh (UP) jointly propose a 2-year research program on middle atmosphere dynamics based on Doppler Rayleigh and Raman lidar observations combined with other optical measurements obtained at Bear Lake Observatory (BLO) and measurements of winds, densities, and temperatures obtained from balloon and rocket flights. (Proposals have been submitted by three institutions using the same text, but different budgets; UP will support this effort through current NSF funding.) CEDAR funding made possible the installation in Utah of a Nd:YAG Rayleigh lidar system that had been developed at UMD and moved to USU to be part of the BLO facilities. The possible altitude coverage has been extended upward to 75 km with the addition of a 6 times more powerful frequency-stable Nd:YAG laser that was purchased by CU for use with the lidar Consortium system. This upgrade of the Maryland lidar facility also includes one additional detector channel, which is a Raman 607 nm channel that extends profile observations of temperature structure downward to the ground from 30 km. The first year of this proposed effort would continue observations of components - a high-resolution Fabry Perot etalon and a double-axis mirror system - that are necessary for measuring the Doppler shift of the backscattered Rayleigh and Mie lidar spectra to observe line-of-sight winds in the middle atmosphere. A small radar system will be added to observe line-of-sight winds in the middle atmosphere. A small radar system will be added to shut off the laser transmitter when any aircraft is near the beam. A new lidar transmission channel will be added (607 nm) based on Raman-shifting the Nd laser output in a high pressure Raman cell. Upon completion of these instrumental modifications at the beginning of the second year of the grant award, application of the new Doppler lidar would collect vertical profiles of middle atmosphere winds and temperature from clear-air portions of the atmosphere above 10 km by using the laser returns from Mie (particulate) scattering and Rayleigh scattering at 532 nm. These profiles will provide the basis for examining the occurrence, structure, interaction, and variability of the jet stream, planetary waves, tides, and gravity waves in the middle atmosphere above the extended mountainous region of the American Rocky Mountain chain. The oblique propagation of these waves through the middle atmosphere as filtered by the prevailing winds in the middle atmosphere will be related to the dynamic activity simultaneously observed in the mesopause region by several instruments at BLO. Correlative observations of temperature, density, and winds will be made between the lidar and a combination of balloons and rockets. A by- product of the PIs observations will be the measurement of aerosol backscatter and extinction in high clouds, particularly thin cirrus, and the detection of stratospheric aerosols.

This is an Academic Research Infrastructure project to upgrade an existing lidar system at Utah State University (USU). It is a collaborative effort that includes investigators from USU, the University of Maryland, Clemson University, the University of Pittsburgh, and University College London. The lidar system provides measurements from which continuous profiles of atmospheric temperatures, densities and winds can be derived. The results will be used to study the transport of energy and momentum from the lower atmosphere to the mesosphere and lower thermosphere. The continuous observations over a long period of time will shed light on climatological questions relating to global change. The upgrade to the lidar system will increase the sensitivity of the instrument by about a factor of thirty. This is to be accomplished by constructing a telescope with a collecting area of 5 square meters. The project includes the construction of a building to house the lidar on the top of the Science and Engineering Building at USU. After the upgrade the lidar system will be one of the most powerful of its kind in the world. The data will be made available to atmospheric scientists and students.

9402823 Wickwar This project will be a one-year collaboratory effort involving Utah State University, the University of Maryland, Clemson University, the University of Pittsburgh, and University College London to upgrade its current capability to include a state-of-the- art resonance-scatter lidar system. In addition to significantly enhancing the atmospheric science, the development of this resonance lidar will mark the transfer of a well-tested laboratory technique to study the atmosphere. After its development and initial use in Utah, the PIs will try this system, or part of it, at the Polar Cap Observatory. At this high-latitude location, the observations could be very useful for examining the winds and temperatures inside and outside the polar vortex as well as the occurrence of ice clouds to determine temperature conditions at time of formation. ***

The observations of the middle and upper atmosphere that can be made at Bear Lake Observatory are vital to the CEDAR objectives of studying coupling among different regions of the atmosphere. Mid-latitude observations provide a very different perspective of coupling compared to those made in the auroral zone and polar cap or in the equatorial region. There are two categories of problems that are particularly amenable to study from a mid-latitude site, and these are being pursued from BLO. The first studies atmospheric processes where the influence of magnetospheric processes are minimal. The other studies extensions of magnetospheric influences into the mid-latitude region, which may occur from an expansion of the auroral region towards the equator or from enhancements of ring-current effects extending poleward.

The investigators will study the density and temperature structure of the middle atmosphere using two lidars at Utah State University. A Rayleigh scatter lidar will measure temperatures in the altitude range from 30 to 90 km, while a resonance lidar will probe the atmosphere between 80 and 105 km altitude. The existing Rayleigh lidar will be repaired and operated for about 100 hours during the coming winter. The alexandrite lidar, currently being developed, will be deployed and tested. The coordinated observations with co-located optical instruments will allow studies of the dynamics of the middle atmosphere, including gravity waves, neutral winds, and mesospheric inversion layers.***

Researchers use the Atmospheric Lidar Observatory to couple lower portion of the atmosphere with the upper mesosphere and lower thermosphere. Based on lidar observations of mid-stratosphere to lower thermosphere temperatures, this emphasizes the transition region between the upper mesosphere and lower thermosphere. Using a much larger telescope, they're able to precisely determine Rayleigh-scatter temperatures and time resolution in the upper mesosphere, and extend maximum altitude above 100 kilometers. Nightly averaged lidar temperatures are used to study seasonal variations in the transition region, especially (1) the mesopause altitude and structure near 87 and 102 kilometers, (2) the relationship between high-altitude summer inversion layers (by Rayleigh lidar) and an inversion layer near 90 kilometers (by sodium lidar), (3) the behavior of vertical wave-like appearance of mesospheric inversion layers to higher altitudes. These nightly temporal variations (or their monthly averages) examine time-varying phenomena, such as tides and downward/upward phase progression of mesospheric inversion layers.

This investigators will upgrade Rayleigh scatter and resonance lidars at the Atmospheric Lidar Observatory (ALO) at the Center for Atmospheric and Space Sciences (CASS) at Utah State University. The upgrade includes detectors and a data acquisition system so that scientific observations can be made with the two lidar systems from the stratosphere into the lower thermosphere. Currently, there is one detector and a one-channel data acquisition system. The funds will be used to purchase new detectors for both lidars, a data acquisition system, and software for controlling the data acquisition and telescope pointing. This combination of hardware and software will enable ALO to contribute middle atmosphere temperature and wind observations in support of CEDAR/TIMED science goals. CEDAR, which stands for Coupling, Energetics, and Dynamics of Atmospheric Regions, is a global change program that combines theoretical modeling with ground-based measurements to study the upper atmosphere and ionosphere. TIMED, for Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics, is a NASA satellite program to study similar regions of the atmosphere. The joint CEDAR/TIMED program aims to coordinate ground-based and space-based observations to achieve better understanding of physical processes in the lower thermosphere and ionosphere.

The investigators will use observations from the Atmospheric Lidar Observatory at Utah State University to study the temperature structure of the mesosphere and lower thermosphere. A recent upgrade to the lidar has increased the sensitivity of the system by a factor of 30. The first task is to continue and extend ongoing research that involves comparison of measured temperatures with those computed using a first-principles model. Resolution of discrepancies will reveal information about the role of gravity waves and chemistry in heating, and the effects of the large-scale circulation pattern. The second task is to relate processes occurring below 80 km altitude with processes at higher altitudes where measurements have not been possible before. The third task is to look for effects of stratospheric winds and waves in the lower thermosphere. Finally, the lidar will be used to look for further evidence of noctilucent cloud formation at mid-latitudes. Previously confined to high latitudes only, the appearance of a noctilucent cloud over Utah in June of 1999 may be an indication of cooler mesospheric temperatures caused by global climate change.

Eleven years of Rayleigh lidar data are analyzed to reveal cyclic and long-term behavior of mesospheric temperature at the Atmospheric Lidar Observatory (ALO) at Utah State University. The temperature climatology is compared with results from other lidars (in particular the lidar at Colorado State University), from satellites (including HALOE and SABER data), from imagers using OH rotational temperature derivations, and from empirical models (MSIS-90 and CIRA86). Climatology of gravity wave Brunt-Vaisala frequencies and potential energies are also developed using the extant data, and a search is made to determine if meteorological variations appear in the lidar data after propagation from the troposphere to the mesosphere.

TThis award is to operate a sodium and Rayleigh lidar systems in the middle latitudes of the Northern Hemisphere (at Logan, Utah). This combined lidar system would be used to undertake correlative studies, addressing new challenges in mesosphere and lower thermosphere (MLT) dynamics as well as extending ongoing work on the study of the interactions of the ionospheric plasma with the neutral atmosphere through collisional interactions. The systems would be capable of measuring three-dimensional wind, neutral temperature and sodium density profiles at high vertical resolution and temporal cadence with a temperature profile for the range from 30 to 115 km and a wind profile for the range from 80 to 105 km. When neutral Na is present at higher altitudes (possibly as a result of sporadic layer formations) the wind and temperature observations can then be extended up to ­140 km into the lower thermosphere. This unprecedented vertical measurement range will, for the first time, allow waves to be studied all the way from the region where they are initiated up to the region where they die out. The facility will also represent an excellent means of training young optical engineering physicists that would then be well suited for many possible career paths in academia and industrial research.

The major scientific goals of the research include the following objectives:
1. characterization of gravity wave (GW) propagation, refraction, ducting, and energy and momentum transports in variable environments, e.g., MLT responses to stratospheric warmings,
2. quantification of GW instability dynamics driving energy and momentum deposition, turbulence, heat, momentum, and constituent transports, and mixing,
3. understanding the interactions of GWs with tides and planetary waves, their influences on these fields, and the evolution of the wave spectrum with altitude, and
4. contributing to an improved understanding of ion-neutral coupling in the E region.
Studies employing the USU resonance and Rayleigh lidar systems will benefit from current and pending measurement capabilities at the Bear Lake Observatory located nearby the Logan lidar site.