The Waves and Coupling Theme: Scientific Overview

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The Waves and Coupling Theme Scientific Overview

• William Ward (wward_at_unb.ca), Alan Manson, Tatyana
  Chshyolkova, Young-Min Cho, Dragan Veselinovic,
  Ding Yi Wang, Tom Duck, Gordon Shepherd, Marianna
  Shepherd, Robert Sica, Kimberly Strong, Jim
  Whiteway
• (University of New Brunswick, University of
  Saskatchewan, York University, University of
  Toronto)

Picture coutesy of P. Fogal
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Summary

• Observatory and theme description
• Scientific context
• Instruments and participants
• Preliminary Results
• Scientific studies

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Waves and Coupling Processes Theme

• Investigates the wave signatures and coupling
  between heights and regions from a polar
  perspective.
• The instrumentation provides observations from
  the ground to the mesopause (100 km).
• Wave investigations include gravity waves, tides
  and planetary waves and their relationship to
  large scale conditions.
• Phenomena of interest are those which occur as a
  result of this coupling and the waves themselves
  (sudden stratospheric warmings, constituent, wind
  and temperature variability, airglow signatures,
  noctilucent clouds, etc.).
• With observations from other sites, assimilation
  and model output, and satellite observations
  these observations can be placed in global
  context and their broader relevance determined.

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Scientific Context
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Circulation Schematic
Summer
Winter
Large-scale circulation tropical and
mesopause Wave sources Convection, topography,
jet instability Gravity waves and
wave-driven circulation Thermospheeic tides and
dynamics
particle precipitation
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T Annual Cycle (40, 60, 80, 100 km, CMAM)
The Arctic summer mesopause at 88 km is the
coldest-known place (130 K) in the terrestrial
atmosphere and is 60 K colder in summer than
winter. Indirect evidence has suggested that the
summer mesopause temperatures in the Antarctic
are a few Kelvin warmer than in the Arctic.
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Coupling Processes
Waves-Wind-Thermal-Constituent Structures are
coupled The coupling between heights and
regions from a polar perspective.
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Mesosphere/Lower Thermosphere
130
Dissociation CO
, O
2
2
O
h
n

Þ
O O
120
2
Thermosphere
Molecular Diffusion
110
CO
NLTE Processes
2
Large Amplitude Wave Motion
Height (km)
100
Tidal /Gravity Wave Breakdown
1
Airglow O(
S), OH, O
2
90
Recombination CO, O
OOM
Þ
O
M
2
Mesosphere
Chemical Heating
80
70
150
200
250
300
350
400
450
500
550
Temperature (K)
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Proposed Winter Polar Dynamical Structure
Redder (bluer) colors depict warmer (cooler)
temperatures. The positive columnar region of
PV is at the center of the vortex. The strong
jet surrounding the region of PV weakens as one
goes into the quasi-stationary core or outside of
the vortex altogether. Darker contours indicate
stronger westerly. Transparent, upward arrows
conceptualize relative gravity wave activity.
Schematic of the overall configuration of the
Arctic polar vortex as diagnosed from a
hypothetical positive region of potential
vorticity (i.e., a high potential vorticity
anomaly). From Gerrard et al., 2002.
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WCPT Areas of Investigation

• Although the general ideas on the circulation,
  transport and dynamics have been formulated and
  are generally accepted, experimental verification
  is still required (especially the forcing
  mechanisms and transport).
• Mean conditions (wind and temperature), waves of
  various scales, and constituents will be
  determined using the PEARL instrumentation.
• We will use the natural variability of conditions
  over Eureka (i.e. vortex position, tropospheric
  conditions, ) to allow different atmospheric
  conditions to be examined.
• Satellite observations, assimilated fields and
  models will provide contextual information.

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Instrumentation and People
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Instrumentation Waves and Coupling Theme
indicates instrument installation not complete

• Rayleigh/Mie/Raman Lidar (RMR) (Mentor T. Duck)
  will measure profiles of tropospheric aerosols,
  clouds, diamond dust, temperatures, and water
  vapour. 
• Ozone Lidars (Mentor R. Sica, J. Whiteway) Two
  ozone lidars will provide measurements of the
  ozone distribution with height (ozone profile)
  from ground level up to the lower stratosphere
  (height of 20 km), and from the lower
  stratosphere to 80 km.
• Very High Frequency Radar (VHF Radar/Meteor
  Radar) (Mentors A. Manson, S. Argall, Chris
  Meek). This provides measurements of the
  horizontal and vertical components of winds in
  the range 0.5-16 km altitude. In meteor-detection
  mode horizontal winds (80-100km) are available,
  effectively continuously in time, with data
  resolution of 3 km and 1 hour.
• Spectral Airglow Temperature Imager (SATI)
  (Mentor M. Shepherd) is a two-channel,
  Fabry-Perot interferometer. It monitors the
  dynamics and temperature in the upper mesosphere
  by alternate observations of the O2 atmospheric
  (0-1) nightglow emission layer at 94 km and the
  OH Meinel (6-2) layer at 87 km.

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Instrumentation Waves and Coupling Theme
indicates instrument installation not complete

• All-Sky Imager (Mentor W. Ward) The all-sky
  imager is designed to image airglow emissions
  within 10 degrees of the horizon at a spatial
  resolution of 1 km (elevation angle of 60
  degrees). It will aid in the interpretation of
  the other optical instruments and determine
  gravity wave parameters from the fine scale
  structure in the airglow emissions.
• Michelson Wind Interferometer (E-region wind
  interferometer - ERWIN) (Mentor W. Ward) is an
  interferometer for measuring mesospheric winds
  through a measurement of airglow emission,
  specifically OH, O2 and OI. This combination
  yields wind speed and radial direction for 3
  altitudes between 87-97 km.
• Fourier Transform Spectrometer (FTS) (Mentor K.
  Strong) Using the Sun or Moon as a source, the
  FTS scans result in absorption spectra that will
  yield the amount of an atmospheric constituent
  (column amount) and some information about its
  distribution (profile information).
• UV-Visible Grating Spectrometer (UV-VIS) (Mentor
  K. Strong) will be used to record UV-visible
  absorption spectra of the light scattered from
  the zenith sky to retrieve vertical columns of
  O3, NO2, NO3, BrO, and OClO.

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Data Analysis and Interpretation

• Ding Yi Wang Research Associate (UNB), working
  on analysis of data, coordinating the results
  from various instruments, providing satellite
  (MIPAS, MLS, TIMED) and model results relevant to
  PEARL.
• Tatyana Chshyolkova PDF (USask), Contextual
  information on the state of the middle atmosphere
  and the analysis of wave data.
• Young-Min Cho PDF (York), working on the
  analysis of the SATI instrument.
• Dragan Veselinovic Masters Student (UNB),
  development of the All Sky Imager and analysis of
  the data.
• Collaborators T. Shepherd (University of
  Toronto), J. McConnell (York University), S.
  Argall (University of Western Ontario)

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Viewing Location in Sky
Horizon
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Spectral Airglow Temperature Imager
Young-Min Cho
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All-Sky Imager
M.J. Taylor
D. Veselinovic
KEO Scientific
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ERWIN II
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Radar Winds January 2007
C. Meek
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Preliminary Results
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SKIYMET MWR at Eureka and MFR at
Saskatoon (Manson Meek)
SemeDiurnal
From Manson Meek
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Diurnal Tidal Signatures in CMAM Latitude and
zonal wave number cross section at 95 km
zonal wave number Negative eastward positive
westward J. Du
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CMAM Annual Cycle of Diurnal Tidal Amplitude
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Vortex Structure

• Representation of the polar vortex (blue) and
  anticyclones (orange) from ?500 to 2000 K
  (20-50 km) isentropic surface on December 25th,
  2004 January 1st, February 1st, and February
  25th, 2005.
• (T. Chshyolkova)

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Eureka Monthly Mean U and T
CMAM Zonal Wind
CMAM T
MIPAS 2002 T
AURA MLS 2006 T
D. Wang
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Scientific Studies
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Transport

• Airglow signatures (SATI, Imager, Erwin) are
  related to atomic oxygen.
• Possible correlations with downward transport of
  NOx, NOy (NO, NO2, HNO3).

.
Randall et al., 2006
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NOx and NOy in atmospheric chemistry

• The three principal reactions producing thermal
  NOx (Extended Zeldovich Mechanism)
• N2 O ? NO N
• N O2? NO O
• N OH ? NO H
• Nitrogen dioxide reacts with water
• 2NO2 H2O ? HNO2 HNO3
• 3HNO2 ? HNO3 2NO H2O
• 4NO 3O2 2H2O ? 4HNO3

.
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Gravity Waves

• Short term variations in temperature and wind are
  often related to gravity waves (meteor radar,
  SATI, ERWIN, lidar, imager).
• The imager provides information on the
  propagation direction and wave characteristics.
• It also provides information for the other
  instruments.
• Winds from the meteor radar and ERWIN provide
  background wind needed to interpret the gravity
  waves.
• Together this instrumentation provides multiple
  perspectives on gravity waves (various heights,
  different observables, various wave parameters).
• The wave amplitudes will be correlated with
  conditions in the troposphere and stratosphere,
  and other large scale waves.

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Tides and Planetary Waves

• Longer term variability in observables provides
  information on large scale waves (wind,
  temperature, and airglow variations imager,
  SATI, ERWIN, meteor radar, lidar).
• These variations will be interpreted along with
  satellite observations and observations from
  other stations which can provide spatial
  information and help identify the waves.
• Correlations between tidal and planetary wave
  amplitudes and amplitudes in the stratosphere and
  mesosphere will be examined.

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Sudden Stratospheric Warmings
Sudden stratospheric warming (Day 30, Arctic, 40
km, T increased, U reversed) produce signatures
throughout the atmosphere

• These figures are from the extended CMAM and
  indicate how these signatures vary with height.
• We will look for correlations between the
  various observation types

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Consistent Wind, Temperature and Constituents

• The temperature, wind and airglow measurements
  with SATI, ERWIN and the Imager are integrated
  quantities.
• The meteor radar provides wind profiles and the
  lidar temperature profiles.
• We will investigate the possibility of developing
  a self-consistent vertical picture of wind,
  temperature, and atomic oxygen using the
  information from all the instruments.
• Wind and temperature information has been used in
  the past to validate radar temperature
  measurements (Hocking, 2007)
• There is a radar capability which is being
  developed for temperature measurements using
  diffusion time for the echos. However it requires
  the temperature gradient to work. The earlier
  work used the lidar to provide the temperature
  measurements and a model for the radar
  temperatures. We hope to use the lidar to provide
  a temperature profile. This however might not
  work if the lidar doesn't go high enough. In that
  case we will use SATI temperatures.

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Plans for 2007/2008

• Implementation of the full instrument complement
  relevant to this theme at Eureka and analysis of
  the data.
• Development of contextual information (models,
  assimilation, satellite observations).
• Analysis of wave signatures from the tropopause
  up in wind, temperature and constituents (ozone,
  oxygen).
• Establish collaborations with other Arctic
  stations.
• Special events (warmings, particle precipitation)