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Abstracts from 2008/2009
19/9/08 James Anstey: Northern Hemisphere polar vortex response to QBO phase in reanalysis data
and in the CMAM
It has long been noted that the interannual variability of the
stratospheric polar vortex in winter appears to be correlated with the
phase of the equatorial quasi-biennial oscillation (QBO) - a phenomenon
referred to as the Holton-Tan Effect (HTE). The correlation in early
Northern Hemisphere winter is quite robust over the 50-year observational
record, but the robustness of the late winter HTE has been a subject of
debate. Using a long (150 year) CMAM run in which a QBO occurs, and in
which no external forcings are imposed, we examine the robustness of both
early and late winter HTE signals in the CMAM as well as in the 44-year
record of the ERA-40 reanalysis. Despite the CMAM QBO being unrealistic in
some respects, similarities between the HTE signals that occur in the
model and the reanalysis data are found. This suggests that in spite of
its deficiencies the model simulation of the HTE is not wholly
unrealistic. Additionally, the existence of spontaneously occuring decadal
variability of the HTE signal in the model suggests that a similar type of
variability may also occur in the real atmosphere.
26/9/08 Matt Toohey: Validating the precision of space-based atmospheric measurements
First year physics laboratory students, and especially their
instructors, know the importance of quoting an estimate of the precision
of any measurement: proper interpretation of the measured data may hinge
on the uncertainty of the measurements. Accordingly, space-based
measurements of the chemical composition of the atmosphere usually come
along with precision estimates produced by the retrieval algorithm. The
precision of the measurements is dependent on the instrument and its
measurement technique: as an example, the ACE-FTS measures many
stratospheric trace gas species with quoted precisions on the order of
1%, with many measurements quoted as being precise to _better_ than 1%.
Can we believe these phenomenal precision estimates? How can we prove or
disprove their appropriateness? After reviewing some techniques used to
validate the precision of past satellite measurement data sets, we will
explore the problem of validating the precision of ACE-FTS measurements
03/10/08 Constantine Nenkov: A New Model for Thermal Convection: Implications for the Atmospheres of the Gas Giants
In this talk I will give an overview of the newly developed 3D
Anelastic GCM on icosahedral grid in spherical geometry. The idea
behind this model is to apply it for the study and modeling of
globally convective planetary atmospheres with large extent, like
the atmospheres of Jupiter and Saturn.
I will start with a broad overview of our current understanding about the
physics of the four giant planets in our Solar system. This is a quickly
evolving research field with very important implications for both
Geophysics and Astrophysics. Then I will briefly describe the numerical
technology used in building the model and its most important features.
Here I will show how the model has been tested against established
benchmarks, both in the non-rotating and rotating case, which are
reflected in results from critical Rayleigh number searches in
spherically convective fluid shells.
One of the main goals of this research is to attain a better
assessment of the qualities and constraints of this new model of
thermal convection. In the last part of the talk I will present recent
results from long-term integrations of the model which have relevance
to zonal flow jet formation in the atmospheres of Jupiter and Saturn.
10/10/08 Cristen Adams: What happens when the midday sun goes out? Preliminary measurements of stratospheric ozone and NO2 during the August 1, 2008 solar eclipse above Eureka, Nunavut
In a normal summer on August 1, the atmosphere above Eureka (80oN) would be flooded by 24-hour sunlight. This summer, a 98% solar eclipse above Eureka significantly reduced sunlight to the stratosphere for the first time since the last sunset in mid-April. A solar eclipse provides a rare opportunity to test our understanding of stratospheric photochemistry: what happens when the sunlight reaching the stratosphere is extinguished over the course of an hour? Measurements of ozone and NO2 above Eureka by the PEARL-GBS (Polar Environment Atmospheric Research Laboratory Ground Based Spectrometer), a UV-visible spectrometer, should help us answer this question. Past observations of ozone during eclipses have yielded a variety of results, including decreases and oscillations in ozone concentrations. Photochemistry and thermal instability caused by reduced sunlight to the stratosphere do not explain this ozone variability. Fewer measurements of NO2 have been made during eclipses, but the results have been more consistent: NO2 increases during eclipses, as expected by NO-NO2 chemistry. I will discuss the challenges of taking measurements during eclipses and will present preliminary ozone and NO2 measurements during the August 1, 2008 solar eclipse above Eureka.
17/10/08 Lei Wang: Stationary Wave Theory, Modeling and Applications
The stationary wave, defined as the zonal asymmetries of the atmospheric climatology, is generated by the zonally varying lower boundary, diabatic heating, and the like. The physical interpretation of the stationary wave is highly complicated due to the nonlinear interactions between the surface and the atmosphere, but stationary wave models, usually simplified from dynamical core of GCMs, are still able to explain the existed atmospheric zonal asymmetries under a framework in which those complicated processes such as transients are neglected.
Past stationary wave models largely focused on tropospheric circulation, but the stationary wave field extends into the stratosphere and plays an important dynamical role there. We have developed a stationary wave model that captures both the stratospheric and tropospheric stationary wave fields. This model is used to diagnose the stationary wave response to climate change in the Canadian Middle Atmosphere Model (CMAM) simulations, and it allows us to separately diagnose the effects of changes to the zonally asymmetric component of diabatic heating and changes to the zonal mean basic state on the climate response. The statosphere-troposhpere dynamical coupling was explored by dividing the stationary wave response into four components: the response in the stratosphere / troposphere induced by the forcing in the stratosphere / troposphere. The stratospheric stationary wave field primarily results from the forcings from troposphere, while stratospheric diabatic heating has a minor impact on the tropospheric stationary waves; this impact is seen most strongly in the tropics and subtropics.
24/10/08 Mark Parrington: The impact of the assimilation of ozone from the Tropospheric Emission
Spectrometer on surface ozone across North America
We examine the potential of ozone data retrieved from the Tropospheric
Emission Spectrometer (TES) for constraining background ozone values
across North America in the GEOS-Chem chemical transport model. In a
previous study we demonstrated that assimilation of TES ozone data into
the GEOS-Chem model improves the modeled summertime distribution of free
tropospheric ozone. The results were validated with ozonesonde data from
the IONS-06 campaign. We assess here how changes in the abundance of
background ozone in the free troposphere, following assimilation of TES
data, impact the surface ozone distribution in August 2006. We show that
the assimilation increases the model surface ozone across the continent,
with changes of less than 3 ppbv in the eastern United States and larger
changes of up to 9 ppbv over the western United States. This represents
an increase of 15-25% of background surface ozone over the west coast
and across Canada. We find that despite the good agreement between the
assimilated ozone distribution and the ozonesonde measurements in the free
troposphere, comparisons with surface measurements from the EPA AQS and
Environment Canada NAPS networks show that the assimilation exacerbates
the bias in surface ozone in the model, suggesting a potential model
bias in the ozone precursor emissions or in the downward transport of
ozone into the boundary layer in the model.
31/10/08 Chris Fletcher: Atmospheric Teleconnections Associated with Snow Albedo Feedback in
Response to Climate Change
Climate change is expected to cause reductions in the amount and
spatial extent of snow cover on land. Recent work suggests that this
will exert a local influence on the atmosphere and the hydrology of
snow-margin areas through the snow-albedo feedback (SAF) mechanism. A
significant fraction of variability among IPCC AR4 general circulation
model (GCM) predictions for future summertime climate change over
these areas is related to the models' representation of springtime
SAF. In this study, we demonstrate a nonlocal influence of SAF on the
summertime circulation in the Northern Hemisphere. Our results show
that increased land surface warming in models with stronger SAF is
associated with large-scale sea-level pressure anomalies over the
oceans and a poleward intensified subtropical jet. We find that up to
20-30% of the intermodel spread in projections of the circulation
response to climate change is linearly related to SAF strength.
14/11/08 Andre Erler: The Tropopause Structure in Baroclinic Life-Cycle Experiments
Recent studies found a layer of enhanced static stability above the
extratropical tropopause using a tropopause-based, quasi-Lagrangian
averaging technique (Birner, 2006). I will explore to what extent the
tropopause structure is affected by dynamical mechanisms during baroclinic
wave breaking and I will present results from numerical experiments
showing the formation of a Tropopause Inversion Layer in idealized
baroclinic life-cycles.
A central point in the discussion will be the evolution of the
tropopause over the course of a baroclinic life-cycle. I will provide a
review of classic theories on tropopause formation and an introduction to
baroclinic life-cycle experiments. These two important concepts will then
be applied to the aforementioned Tropopause Inversion Layer.
I will relate the structure of the tropopause to the mechanisms
governing the static stability of the extratropical troposphere and
discuss the tropopause structure in the context of the global
circulation.
21/11/08 Tiffany Shaw: Sensitivity of simulated climate to conservation of
momentum in gravity wave drag parameterization
A realistic simulation of present-day climate requires a representation of
the transfer of momentum and resulting torque exerted by internal gravity
waves, called gravity wave drag. Unfortunately, parameterizations of
gravity wave drag are very poorly constrained by current observations. As
a result, theoretical constraints are very important and one such
constraint is conservation of momentum. Momentum conservation requires
that the parameterized gravity wave momentum flux at the top of the model
be zero and corresponds to the physical boundary condition of no momentum
flux at the top of the atmosphere. Allowing momentum flux to escape the
model domain violates momentum conservation. Here we investigate the
impact of momentum conservation in two sets of Canadian Middle Atmosphere
Model simulations. In the first set, we consider the impact of momentum
conservation on the simulation of present-day climate for a low-lid and
high-lid configuration. In the second set of simulations, we consider the
impact on the modeled response to ozone depletion in the southern
hemisphere. In both sets of experiments we find that the climate displays
significant sensitivity to both momentum conservation and model lid
height. We discuss the implications with regard to the current round of
IPCC model projections.
28/11/08 Jane Liu: Synergistic Use of TES Satellite Data and a Global CTM
for Studies of Tropospheric Ozone in the Middle East
The Tropospheric Emission Spectrometer (TES) on the NASA EOS Aura satellite provides a unique dataset of simultaneous vertical profile retrievals of ozone, water vapour (H2O), and deuterated water vapour (HDO) in the troposphere. In this study, we use the GEOS-Chem chemical transport model to interpret observations of tropospheric ozone from the Tropospheric Emission Spectrometer (TES) satellite instrument in summer 2005. Observations from TES reveal elevated ozone in the middle troposphere (500-400 hPa) across North Africa and the Middle East. Observed ozone abundances in the middle troposphere are at a maximum in summer and a minimum in winter. This enhancement has some similarities to and differences from previously predicted summertime “Middle East ozone maximum”. This ozone enhancement is associated with the Arabian and Sahara anticyclones, centered over the Zagros and Atlas Mountains, respectively. These anticyclones isolate the middle troposphere over northeast Africa and the Middle East, with westerlies to the north and easterlies to the south, facilitating the build-up of ozone. Over the Middle East, we find that in situ production and transport from Asia provides comparable contributions of 30-35% to the ozone buildup. Transport from the boundary layer accounts for about 25% of the local Middle Eastern contribution to the ozone enhancement in the middle troposphere. This upward transport of boundary layer air is associated with orographic lifting along the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water (HDO/H2O).
05/12/08 Yonggang Liu: Interaction between Earth Rotation and Climate
This presentation will be a review of the interaction between Earth
rotation (both direction and speed of polar wander and the length of day)
and climate at various timescales (from days to tens of millions of
years). The orders of magnitude of these variations include centimeter
scale wobbles of the rotation axis in space to 90 degree true polar wander
flips of the rotation axis with respect to surface geography. The review
will focus primarily upon the ongoing kilo-year timescale wander of the
spin axis which is a direct result of the forcing associated with the last
ice age. Also to be discussed will be the possibility of a million-year
timescale Inertial Interchange True Polar Wander (IITPW) instability,
which could provide a reasonable explanation for the late Neoproterozoic
(~700 - 543Ma) low-latitude glacio-genic deposits found on most of the
continents.
12/12/08 Peter Hitchcock: Newtonian Cooling in the Middle Atmosphere
Simple dynamical models of the stratosphere commonly approximate the effects of radiation by a linear damping term--a parameterization known as Newtonian cooling. But how valid is this approximation? I will review the physical justification for Newtonian cooling, and present a simple method for diagnosing effective Newtonian cooling coefficients from a GCM with a more detailed radiation code.
Applying this method to the Canadian Middle Atmosphere Model indicates that the approximation works quite well through most of the stratosphere, though the damping coefficient varies strongly with latitude and season, as well as with height. An important exception is during the spring in the Antarctic lower stratosphere, where non-local effects play a significant role. This may suggest the need for more detailed radiative codes in mechanistic modelling studies of the final warming in the Southern Hemisphere.
09/01/09 Jeff Taylor: The Little Satellite that Could: Quantifying Inter-Annual Variability of Ozone and related Trace Gases in the Arctic Stratosphere with Observations from the ACE Satellite
The Atmospheric Chemistry Experiment (ACE) is a Canadian satellite mission
that was launched on-board the SCISAT platform in August 2003. The primary
instrument for the ACE mission is a high-resolution (0.02 cm-1) infrared
Fourier Transform Spectrometer (ACE-FTS) with a spectral range of 750–4400
cm-1. This instrument makes solar-occultation measurements of over 30
different atmospheric trace gases with well-resolved vertical profiles from
the upper troposphere to the lower thermosphere (under cloud-free
conditions). Since operational retrievals began in February 2004, over 15
000 occultation measurements have been made.
The work shown here will highlight the development and first results of an
Arctic trace-gas climatology, based on the first four years of ACE-FTS
observations. Specifically, this study uses derived meteorological
products to map the observations into equivalent latitude space and
ultimately determine the inter-annual variability of O3, HCl, ClONO2, HNO3,
H2O, and ClO. By comparing this climatology with other satellite
observations from the Microwave Limb Sounder (MLS), and measurements made at
the Polar Environment Arctic Research Laboratory (PEARL) in Eureka, Nunavut
(80.05°N, 86.42°W), changes occurring in the concentrations of these Arctic
species can be investigated.
16/01/09 Rebecca Batchelor: A ground-based instrument? What good is that? - Research highlights from the ground-based Fourier transform infrared spectrometer at Eureka
In this world of globe-covering satellite missions and high-resolution models, I am frequently asked “What good is a single ground-based instrument?” This presentation will showcase some of the many things that we’re doing with the new ground-based CANDAC Fourier transform infrared (FTIR) spectrometer at Eureka. To ensure that the presentation appeals to as many atmospheric group people as possible, these highlights will include, in no particular order or promise of completion: measurements, models (including CMAM and GEOS-CHEM), dynamics, satellite validation and pretty pictures.
23/01/09 Quoying Qin: A global inventory of stratospheric NOy from ACE-FTS measurements
The total odd nitrogen (NOy) budget in the stratosphere and lower
mesosphere has been determined using the Atmospheric Chemistry Experiment
Fourier Transform Spectrometer (ACE-FTS) measurements of NO, NO2, N2O5,
HNO3, ClONO2, and HNO4. ACE-FTS has been measuring these six major NOy
species from orbit since February 2004 using infrared solar occultation.
A global NOy climatology of monthly mean volume mixing ratio profiles and
their standard deviations as a function of latitude has been constructed
using the first four years of ACE-FTS data.Additional annual zonal means
of NOy and its partitioning have been generated for five latitude bands
(60-90N, 30-60N, 30S-30N, 30-60S, and 60-90S) for four years of data. The
resulting annual inventories of NOy show differences that can be
attributed to solar activity, descent, and denitrification. Seasonal
variations have also been assessed, taking into account the spatial and
temporal sampling of the ACE occultation geometry. This ACE-FTS NOy data
set will be useful for model validation and atmospheric studies.
30/01/09 Dave MacKenzie: Seasonal Variations in the Mixing Layer in the UTLS
Changes in O3 in the upper troposphere and lower stratosphere (UTLS)
can influence the climate system. Furthermore, stratosphere-
troposphere exchange events (STE) associated with these changes can
significantly impact air quality. Consequently, studies aimed at
understanding UTLS variability and the causes of this variability have
become more frequent. Most recent studies in this area have focused
on aircraft and satellite data. The work presented in this talk
investigates the representation of mixing in the UTLS in numerical
models, focusing on the GEOS-Chem and the Global Modeling Initiative
(GMI) COMBO models. In particular, tracer-tracer correlations are used
to examine regional and seasonal variations in UTLS mixing in the
models.
06/02/09 Melissa Gervais: The Interrelations Between Precipitation,
Climate Oscillations and Trade Winds in Central America
Central America is a region with high biodiversity due to its unique cloud
forest habitats. These cloud forests are caused by the interaction between
the easterly trade winds and the high topography of the region. The species
that inhabit them are highly susceptible to changes in precipitation. As a
result, we strive to obtain a better understanding of changes in Central
American precipitation on an interannual time scale. Specifically, two
climate oscillations, the Atlantic Nino and the Pacific El Nino Southern
Oscillation, are examined as possible candidates for producing this
variability. Using precipitation station data in Central America, NCEP
moisture transport fields and indices of climate oscillations, we
investigate the interrelationships between these variables. From this it is
shown that in periods when the El Nino Southern Oscillation is high and the
Atlantic Nino is low there is a decrease in precipitation in Central
America. This relationship could help improve our ability to predict
changes in Central American precipitation in the future.
13/02/09 Zhe Jiang: Quantifying the impact of aggregation errors and model transport biases
on top-down estimates of carbon monoxide emissions using satellite's
observations
We conducted an inverse analysis of atmospheric CO, using the GEOS-Chem
model and observations from the MOPITT satellite instrument, to quantify
the potential contribution of model transport error and aggregation
errors to top-down source estimates. We focus on quantifying CO
emissions for September 2000, during the biomass burning season. Using a
4-dimensional variational data assimilation scheme, we optimize the CO
emissions on the 2°x2.5° grid of the model. The high-resolution, a
posteriori source estimates are compared with estimates obtained from a
coarse resolution, analytical Bayesian inversion to quantify the impact
of aggregation errors in the coarse resolution inversion on the source
estimates. We also carry out the coarse resolution analytical inversion
using two different versions of the GEOS-Chem model, driven with
different transport fields, to isolate the impact on the source
estimates of systematic differences in transport in the models.
13/03/09 Thomas Walker: Quantifying the impact of long-range transport of pollution on ozone
abundances in the Arctic troposphere
We use the GEOS-Chem global chemical transport model and its adjoint,
together with satellite and in situ observation of tropospheric ozone, to
assess the impact of transport of pollution from midlatitudes on the
abundance of ozone in the Arctic. The model reproduces well the seasonal
cycle in the abundances of PAN and ozone as measured at the surface at
Alert. However, relative to ozonesonde measurements, the model
overestimates ozone in the middle and upper troposphere in spring, while
it underestimates ozone in summer. We examine the information gained by
assimilating tropospheric ozone profile retrievals from the Tropospheric
Emission Spectrometer (TES) satellite instrument at midlatitudes to
provide an improved boundary condition for ozone at midlatitudes to better
quantify the transport of ozone into the Arctic. We find that the
assimilation corrects model biases relative to sondes in the Arctic free
troposphere, implying an increase in the net northward ozone flux. We
also use the adjoint model to conduct a detailed analysis of the
sensitivity of the modeled ozone abundances in the Arctic to midlatitude
precursor emissions.
20/03/09 Heather Andres: Exploring the Effects of Different Insolation Models on
Modelled Surface Climate Variables
Resolving the different roles that natural and anthropogenic forcings
have played in the climate system over the past century has been the
central effort of many coupled, atmosphere-ocean modelling studies.
In particular, the effects of total solar irradiance (TSI) variability
on the climate system have been emphasised in these studies, due to
the perceived strength of century-scale, solar variability in TSI
models. However, estimates of the amplitude of this variability were
reduced dramatically in 2005 as a consequence of new developments in
solar modelling. Nevertheless, many climate models continue to employ
the earlier TSI models.
I will present the results of changing TSI models on modelled surface
and sea surface temperatures. In order to address this question, I
have analysed three sets of global warming simulations from 1870 to
2000 based on the National Center for Atmospheric Research Community
Climate System Model 3.0 (CCSM3). These simulations include both
anthropogenic and natural forcings, consistent with those used in the
CCSM3 analyses performed in support of the 4th IPCC Assessment Report.
The two sets differ only in their TSI datasets: one published by
Lean et al (1995) and the second by Wang et al (2005). By
intercomparing the variations of surface climate features produced by
each of these sets, I will identify some differences that emerge due
to the change in solar forcing alone.
03/04/09 Gordan R. Stuhne: Advances in Glacial and Ocean Modeling Technology:
Unstructured Grids and New Numerical Methods
I will present results from ongoing work relating to the
development of numerical methods for climate system
modeling. My latest research is geared towards the enhancement
of the University of Toronto Glacial Systems Model (GSM),
although the new techniques are widely applicable, and
have previously been tested successfully in tidal and
ocean modeling contexts. Earlier versions of the GSM have been
employed for paleoclimate applications such as the
simulation of the glacial history of Greenland, and
my work aims to improve this code base and then generalize
it with features such as unstructured grids and
finite volume (FV) methods. When spatial domains are
discretized using general triangulations, resolution can be
arbitrarily enhanced near dynamically crucial ice margins and
ice rivers. I have already tested unstructured grid FV
methods in the context of shallow-water tidal modeling,
and results will be shown to illustrate how the GSM is
based on similar fundamental physics. The original
ice-sheet model is being reverse engineered to
facilitate the ongoing development of the generalized
modeling framework.
17/04/09 Karen Smith: The role of the stationary wave field in the
stratosphere-troposphere coupling response to extratropical surface
cooling
Observational studies indicate that the correlation between autumnal snow
cover anomalies over Eurasia and wintertime circulation anomalies projects
significantly onto the Northern Annular Mode (NAM). Forced general
circulation model (GCM) experiments reveal that a large autumnal Eurasian
snow forcing generates a negative NAM stratosphere-troposphere coupling
response that propagates down to the surface within several weeks.
Contrastingly, this response is not found in unforced GCM runs with
seasonally varying snow cover. Potential dynamical reasons for this
discrepancy are probed by imposing an idealized Eurasian snow forcing in a
relatively simple GCM.
A decomposition of the meridional eddy heatflux response over the first
several weeks indicates that the linear term, i.e. the term that includes
correlations with the background stationary wave field, dominates the
response and yields an overall negative meridional eddy heatflux response
in the stratosphere to the surface cooling. In general, correlations
between the response and the stationary wave field appear to be an
important factor in determining the nature of the response to surface
cooling in this model.
08/05/09 Robert Field: Human amplification of drought-induced biomass burning in Indonesia since 1960
Much of the interannual variability in global atmospheric carbon dioxide concentrations has been attributed to variability of emissions from biomass burning. Under drought conditions, burning in Indonesia is a disproportionate contributor to these emissions, as seen in the 1997/98 haze disaster. Yet our understanding of the frequency, severity and underlying causes of severe biomass burning in Indonesia is limited because of the absence of satellite data that are useful for fire monitoring before the mid-1990s. Here we present a continuous monthly record of severe burning events from 1960 to 2006 using the visibility reported at airports in the region, which was found to be an excellent proxy for fire activity. We find that these fires cause extremely poor air quality conditions and that they occur only during years when precipitation falls below a well defined threshold. Historically, large fire events have occurred in Sumatra at least since the 1960s. By contrast, the first large fires are recorded in Kalimantan (Indonesian Borneo) in the 1980s, despite earlier severe droughts. We attribute this difference to different patterns of changes in land use and population density. Fires in Indonesia have often been linked with El Niño, but we find that the Indian Ocean Dipole pattern is as important a contributing factor.
15/05/09 Rodica Lindenmaier: Stratospheric Trace Gas Measurements, Ozone Microwindows and ACE Validation at Eureka
A Bruker 125HR Fourier Transform Spectrometer was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut in the summer of 2006 to study atmospheric composition. Using the optimal estimation method, typically over a limited spectra region called a microwindow, information about the vertical distribution of trace gas species that have absorption bands in the mid-infrared spectral range can be retrieved. Total and partial columns can also be determined to show the temporal evolution of the target gas. For ozone in particular, retrievals have been performed using several of its many mid-infrared absorption features, resulting in a lack of consistency in the literature in the microwindows chosen for retrievals.
I focused my work on the optimization of the ozone retrieval, assessing a set of 22 microwindows between 780 and 3052 cm-1 to determine which is best suited to conditions at Eureka. The 1000 to 1004.5 cm-1 spectral interval is shown to be the most sensitive to both the stratosphere and troposphere. This microwindow gives the highest number of degrees of freedom for signal (~7 for total column), and the smallest total error (4.3%) compared with 21 other spectral regions. Retrievals performed with this microwindow agree well with results obtained from other instruments on site.
SCISAT, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sounding of the Earth's atmosphere and was launched on August 12, 2003. Its primary instrument is a high spectral resolution Fourier Transform Spectrometer (FTS) measuring sequences of atmospheric absorption spectra in solar occultation. From these spectra, the vertical distribution of trace gases can be determined. Results of the Bruker 125HR comparisons with the ACE-FTS, made with the purpose of the validation of the satellite measurements, will be also shown.
Brewer Seminar site maintained by Karen Smith. Last updated 13 May 2009.
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