|
| Name of Project | PI/Inst. | Dates/locale | ATD asset(s) |
|---|---|---|---|
| VTMX | Parsons et al, NCAR | Oct. 00 Salt Lake City |
MAPR, TAOS |
| CAMEX | J. Rothermel, NASA | Aug-Sept. 01 Atlantic & Gulf of Mexico |
GPS dropsonde w/ automated launcher |
| ISCAT | D. Davis, Geo. Tech | Nov. 00-Jan. 01 | ISFF |
| IMPROVE I | P. Hobbs, C. Maas, U. Wash. |
Jan-Feb 01 | SPOL, C-130 Dropsonde, UWyo cloud radar |
| Snowfall Reduction | D. Lowenthal, DRI | Jan-Mar 01, Stmboat Spgs, CO |
MAPR |
| ACE-ASIA | B. Huebert, U. HA | Apr 01, off shore Japan, China & Vietnam |
C-130, GPS Drpsnd. |
| PBL-AOE | O. Persson, NOAA/ETL |
Aug 01 | ISFF |
| DYCOMS II | B. Stevens, UCLA | Jun-Jul 01 | C-130, SABL, TDL, GPS Drpsnd |
| PROPHET | J. Moody, UVa | Jun-Aug 01 UMich |
ISFF |
| EPIC | D. Raymond, NMIMT | Aug-Sept 01 Eastern Pacific |
C-130, GPS Drpsnd, SABL |
Verticle
Transport and Mixing Experiment
(VTMX)
VTMX was conducted for the month of October 2000, in and around Salt
Lake City, UT. The US DOE sponsored the program, which involved 60
personnel and 14 different research institutions, including ATD. As
population in the western USA continues to increase, so do pollution
and the importance of reliable weather forecasts. VTMX was aimed at
studying how air moves in the valley, especially overnight during
colder months; the results of the experiment are expected to be
applicable in other cities with similar locations and topography. ATD
deployed its tethered weather balloon (TAOS) and the MAPR. TAOS
makes observations every second or so of winds, air pressure, and
other conditions needed to understand and predict turbulence, while
MAPR looks upward and measures winds in clear air. This was MAPR's
first field expedition with its improved hardware and software, which
added rapid-measurement capabilities.
MAPR deployed in VTMX
An Investigation of Sulfur Chemistry in the Antarctic Troposphere
(ISCAT)
ATD deployed one ISFF at the South Pole during the austral summer of
2000 - 2001 to quantify fluxes of NO from the snow pack and to gain a
better understanding of mechanisms involved in the recycling of NO
from nitrate ion adsorbed on ice surfaces. Under the ambient
conditions observed at the South Pole, NO is believed to play a major
role in regulating the levels of OH which, in turn, defines the
oxidizing capacity of the near surface polar plateau. D. Davis
(Georgia Tech.) led the research effort to evaluate the hypothesis
that elevated NO levels seen in the South Pole mixed layer resulted from the
NOx emission from the snow pack under the influence of UV radiation.
Snowfall Rate Reduction by Pollution Aerosols
D. Lowenthal (DRI) led this project to study the physical processes
underlying the relationships between pollution-derived sulfate
concentrations and droplet number, between droplet number and size,
and between deoplet size and snowfall rate. This year's program
follows a pilot program that established a significant statistical
relationship among these parameters.
| ATD installed the Multiple Antenna Profililng Radar (MAPR) version of the ISFF below cloud base to measure temperature (by the RASS) and wind profiles. Data collected by the MAPR system in January 2001 near Steamboat Springs, CO will help to define aerosol-cloud interactions. Simultaneous, detailed measurements were taken of in-cloud microphysics and chemistry, and precipitation rate during mixed phase (cloud droplets and snow crystals) precipitation events from a mountaintop site while clouds enveloped the site. The data will be used to test a hypothesis that riming inhibition caused by aerosol-induced shifts in the cloud droplet distribution to smaller sizes decreases snowfall rates. In addition to operating the site, ATD personnel will collaborate with Lowenthal in data analysis. |  |
| Satellite image of dust moving from Mongolia over the Pacific and later discerned in samples taken during Snowfall Rate Reduction Program in Northwest Colorado. |
|
The scientific goal of PBL-AOE, led by O. Persson of NOAA/ETL, with
funding provideded by Stockholm University, was to study the Arctic
boundary layer (ABL) in order to document transitory features found
there. These features include low-level jets, low-level clouds,
gravity waves, and microfronts, all of which affect the transport of
DMS, aerosols, and other atmospheric constituents as well as the
development of the boundary layer itself. The AOE data set is
publicly available via the website. These are
an initial values computed during the field project; no editing or
quality control has been applied. ATD's SSSF installed and manned two stations on pack ice near the North Pole to form a triangle 7-10 km on a side, with a tower site near the Swedish Maritime Administration icebreaker, the Oden, as the third vertex. These stations were deployed for most of a three-week drift. Another station was deployed for two short (4 and 20-hour) periods. It was also deployed for five days at a lead edge to study aerosol emission from the open water. |  |
| The Swedish icebreaker Oden near the North Pole in
PBL-AOE, and the nearby ISSF station.
|
Program for Research on
Oxidants: Photochemistry, Emissions and Transport
(PROPHET)
From the end of June to mid-August 2001, one ISFF was deployed at the
University of Michigan Biological Station. J. Moody (U. Virginia) and
M.A. Carroll (U. Mich) requested the system for a second year, to
support the educational component of their research program, funded
jointly by NSF, DOE and the University of Michigan. PROPHET's
research goal is to investigate the fundamental processes that
determine ozone and related oxidant levels at the rural forested site
in Northern Michigan.
 |
 | |
| The ISS installed in Northwest Michigan | PROPHET students launching sounding balloon |
PROPHET has a significant two-part educational component, one aimed at a residential research experience for undergraduates and the other at interdisciplinary graduate education and research training. Ten university mentors worked with the students involved to operate the ISSS as well as a NOAA dropsonde profiling system that was involved. ATD provided engineering and maintenance backup and cooperation, as well as lectures on the science and observing technologies involved in the program.
The East Pacific Investigation of Climate Processes in the Coupled
Ocean-Atmosphere System (EPIC)
The overall purpose of EPIC was to understand the dynamics of the
coupled ocean-atmosphere system of the eastern Pacific region. This
first phase of EPIC consisted of a study of the cross-equatorial
Hadley circulation, its spatial and temporal variability and
associated oceanic processes along the 95W line of TAO buoys.
D.Raymond (New Mexico Tech.) and colleagues used the C-130, equipped
with a GPS
dropsonde system and SABL, to
study the dynamics, thermodynamics and cloud physics of the Hadley
circulation. The project occurred during August and September 2001.
During last
winter's IMPROVE I
program, ATD implemented real-time full bandwidth transmission of
data from S-Pol to the University of Washington. ATD also developed
full remote control of the radar. Both developments enable 24-hour
operation of the radar with a reduced field staff.
Rotary wave-guide switches
Rotary wave-guide switches
developed by ATD for S-POL have been incorporated in NASA's
polarimetric radar. These switches allow rapid pulse-to-pulse
switching of the radar beam with very good separation.
ISFF hygrothermometer radiation shield
In-situ temperature and relative humidity sensors must be enclosed in
a shield designed to provide good exposure of the sensors to the
ambient air while significantly reducing exposure to short and long
wave radiation. Optimization of the radiation shield design is
particularly critical for remote meteorological stations that have
limited power available for mechanical aspiration of the sensors
within the shield. T. Horst and S. Semmer evaluated the design of
the current ISFF hygrothermometer radiation shield based on wind
tunnel measurements of shield aspiration rates as a function of
ambient wind speed, field intercomparisons of different shield
geometries, and calculations of shield performance using both
analytical and numerical models. A CU engineering graduate student,
B. Fichera, used commercial fluid dynamics software to simulate
the performance of a range of shield geometries. The results of both
field intercomparisons and numerical simulations suggest that the
temperature errors of the current shield design with a flared inlet
are on the order of 0.1 to 0.2 degrees C. Without the flared inlet and
for ambient winds above 5 m/s, temperature errors on sunny days can
exceed 1 degree C.
Icing Detector
Experience from recent projects has shown that
during polar deployments ice build-up on the pyrgeometer radiometers
is difficult to detect in the data, since ice, air, and cloud
temperatures can be quite similar. With stations accessible only
occasionally and with difficulty, manual detection of sensor icing was
impractical. ATD engineers constructed a "dummy sensor" with an
internal optical detector to detect ice on the radiometer dome, a
useful addition to ATD's cold-weather field programs.
FDI RIM on MAPR
Frequency Domain Interferometry Range IMaging
is a technique to greatly improve the range resolution of a wind
profiler. One of ATD's ASP postdocs, Tian Yu, has been working on
this technique with a NOAA profiler. In August, he applied the
technique to MAPR. In late August and early September ATD carried out
a field campaign at Marshall in which RTF ran MAPR and TAOS (below) to
support instrument intercomparison with a lidar operated by a group
from Johns Hopkins.
Application of NIMA to ISS profilers
NIMA (NCAR Improved
Moment Algorithm) software developed in RAP, helps to reanalyze and
clean up wind profiler measurements. RTF adapted
the package to ATD's ISS profilers. ATD ran the system for the PROPHET
project and prepares to run it again for IMPROVE II.
Study of the absolute precision of wind profiler radial velocity
measurements
In collaboration with Goodrich (CU Math Dept.) RTF staff investigated
limits to the precision of wind profiler measurements. Using
simultaneous measurements of radial velocity from a wind profiler and
a lidar, RTF staff removed mean components and turbulent variances of
the wind, leaving a remainder primarily due to instrumental precision
of the two systems. For the profiler, this precision theoretically
becomes a function of signal to noise ratios and spectral widths of
the Doppler spectrum.
Study of the theoretical precision of spaced antenna wind profiler
measurements
With Doviak, Lataitis, Zhang, RTF staff derived measurement standard
deviations associated with several implementations of spaced antenna
wind measurements to determine which implementation to use for a given
set of radar parameters and atmospheric conditions.
TAOS Development
ATD tested a prototype new sonde in a recent in house experiment.
These tests proved that the proposed new sonde design will require
about one third the power of the previous sonde, will be about two
thirds the weight of the previous sonde, will vastly improve data
quality, and will be user friendly, allowing easy integration of
third party and other sensors. The high wind speed balloon will
extend operations to allow for sampling in stable winds up to 45
mph. A new trailer will protect balloons from the elements when not
being used and will hold a fully inflated balloon so limited helium must be
vented between flights. The Hudson Valley Ambient Meteorology Study
(HVAMS) requested TAOS for a project in September and October of next
year.
Deployment of RDMA for airborne aerosol particle measurements
The Radial Differential Mobility Analyzer measures atmospheric
particles in the nucleation mode size range ~8-130 nm diameter to
indicate regions where new particle formation occurs. This instrument,
developed in collaboration with Princeton University, NCAR/ASP, and
the National University of Mexico, was used on the NCAR C-130 during
the ACE-Asia and DYCOMS II field projects.
HRDL Development
In collaboration with NOAA's Environment
Technology Lab, the High Resolution Doppler Lidar was reconfigured on
a smaller optical to enable HRDL to fly on the German (DLR) falcon
aircraft during the IHOP program in 2002. Further development will
allow the HRDL to fit in a C-130 wing pod.
Improvements to the Particle Measuring Systems
Upgrades to one-half of the existing Particle Measuring System (PMS)
probes involving new electronics and communication systems were
completed during FY 2001. They were successfully deployed in
ACE-ASIA, DYCOMS II, and EPIC field projects.
Wyoming Cloud Radar
ATD mounted the University of Wyoming
short wavelength cloud radar on the C-130. This development brings a
new tool to ATD users, extends the utility of the radar system, limited up
to now to King Air deployments, and represents a high level of
cooperation between Wyoming and ATD.
Multichannel
Cloud Radiometer (MCR)
ATD hired a scientific visitor to
improve the operational procedures for routine calibration of this
instrument and to develop additional value-added software so that
users will have robust tools to utilize data from this instrument.
The instrument was deployed in a C-130 pod for the DYCOMS II project.
3-D rendering of SPOL data using the new multi-platform data viewer.
RAF Data Input System
(RAFDIS) Development
Software engineers in ATD's Research Aviation Facility (RAF) designed
and implemented this software package to allow RAF staff to enter
flight report data and flight comments in Web browser forms for
archival in text database files. The package also includes a Web form
and Perl CGI script, which allows RAFDIS users to generate flight
reports from existing database entries. After an initial test during
ACE-Asia, the system will become a routine component of aircraft
deployments. In addition, K. Laursen designed a new graphical
interface now used as the primary site navigation tool on all new
field project Web pages.
Radiosonde Quality Control and Message Generation
ATD refined and modified the Aspen radiosonde quality control package
to meet requirements of NCAR and of the 53rd Weather Reconnaissance
Squadron (the Hurricane Hunters). The Aspen program allows detailed
examination and manipulation of individual soundings. BatchAspen can
process large numbers of soundings without operator interaction,
producing output data files and WMO formatted messages with automatic
quality control. Users made more than 100 downloads of Aspen in the
past year; about 50% of these were by international scientists.
ISFF Software Developments
ATD staff converted all ISFF software to Linux, to allow all ISFF base
computer operations to run on a laptop PC and to significantly reduce
shipping, space, and power requirements during recent deployments in
remote locations (the North and South Poles). Having this software
run under a public-domain operating system also allows ATD to share it
with a wide variety of non-NCAR users. Access to all ISFF data,
including individual samples from high-rate sensors, is now possible
via the WWW. ATD staff wrote a WWW interface to the
NCAR Mass-Store system to allow such users to obtain these archived
data files.
Boundary layer turbulence and fluxes
RTF scientists, in collaboration with scientists from NCAR/MMM, Johns
Hopkins Univ., and Penn. State Univ., investigated interactions
between small and large scale turbulent eddies. Data collected in
September 2000 during the SGS
(Sub-Grid Scale) 2000 field project were used to explore statistical
properties of turbulence partitioned into spatially-resolved and
sub-grid-scale components, as assumed in numerical Large Scale Eddy
Simulation (LES) models. Preliminary work suggests that
sub-grid-scale stresses are not aligned with resolved-scale strains,
an assumption found in almost every LES parameterization of the
sub-grid-scale stress tensor.
Tropical Convection
The Nauru-99
project was carried out around the central Pacific island of Nauru
using two research vessels, aircraft, and stations on the island. ATD
operated two wind profilers and a variety of other instruments on the
R/V Mirai. ATD scientists analysed heating of the boundary layer by
the island as observed by RASS measurements on the R/V Mirai as it
cruised around the island.
Surface energy budgets
ATD scientists and international colleagues designed the EBEX2000 field experiment to determine
why in situ measurements often cannot produce a complete
surface energy balance over plant canopies. The magnitude of heat
storage in the plant canopy and ground was evaluated using soil
temperature gradient sensors designed by ATD and plant samples made by
researchers at the Univ. of California. On average, storage in the
canopy was small though short-term storage can be quite large.
However, heat flux into the soil was quite large -- as much as 30% of
net radiation -- and heat storage in the top few cm of soil can be as
large as the total flux.
Biogeochemical fluxes
ISFF was deployed during ISCAT2000
to determine if emissions of NO from the snow pack could cause high
levels of atmospheric concentrations of NO observed during ISCAT1998.
Modified Bowen ratio method estimates were found to be larger than
those estimated by earlier studies, but consistent with the higher NO
levels seen during both ISCAT1998 and ISCAT2000. As part of this
analysis, ATD and MMM scientists examined methods for determining the
height of the atmospheric mixed layer from near-surface tower data;
early results indicate that spectral methods can produce reasonable
and consistent estimates of the height.