science mtg, oct 24, 2007waves and coupling theme of the pearl the waves and coupling theme:...

Science Mtg, Oct 24, 2007 Waves and Coupling Theme of the PEARL

The Waves and Coupling Theme: Scientific Overview

William Ward ([email protected]), 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


Summary

• Observatory and theme description

• Scientific context

• Instruments and participants

• Preliminary Results

• Scientific studies


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.


Scientific Context


CONVECTION

JET INSTABILITY

TOPOGRAPHY

WAVE-DRIVEN CIRCULATION

MIDDLE ATMOSPHEREGRAVITY WAVES

THERMOSPHERICTIDES & DYNAMICS

TR

OP

O-

SP

HE

RE

ST

RA

TO

SP

HE

RE

ME

SO

SP

HE

RE

TH

ER

MO

SP

HE

RE

Circulation Schematic

Summer Winter

Large-scale circulation: tropical and mesopauseWave sources: Convection, topography, jet instability Gravity waves and wave-driven circulation

Thermospheeic tides and dynamics particle precipitation


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.


Coupling Processes

Thermal

Structure

Thermal wind balance

Radiative Heating and

Cooling

Dissipation, turbulence and

meridional forcing

Transport and Mixing

Wave filtering

Zonal Wind

Structure

Wave Activity(Tropospheric

Sources dominate)

Constituent

Distributions

Mixing/Induced Circulation

Wave induced stress

Thermal

Structure

Thermal wind balanceThermal

Structure

Thermal

Structure



Radiative Heating and

Cooling


meridional forcing


Wave filtering

Zonal Wind

Structure


Sources dominate)

Constituent

Distributions


Wave induced stress


meridional forcing


Wave filtering

Zonal Wind

Structure


Sources dominate)

Constituent

Distributions


Wave induced stress

Waves-Wind-Thermal-Constituent Structures are coupled The coupling between heights and regions from a polar perspective.


150 200 250 300 350 400 450 500 55070

80

90

100

110

120

130

Mesosphere/Lower Thermosphere

Thermosphere

Mesosphere

Molecular Diffusion

Large Amplitude Wave Motion

Tidal /Gravity Wave Breakdown

CO2 NLTE Processes

Dissociation: CO , O

O2 + h O + O

Airglow: O( 1S), OH, O2

Recombination: CO, O

O+O+M O2+M

Chemical Heating

Temperature (K)

Hei

ght

(km

)

2 2


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.


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.


Instrumentation and People


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.


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.


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: Master’s 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)


Viewing Location in Sky

All sky camera [ I ]E

ErwinE

[u, I]EE

E

E

SATI [ T, I]

X

Lidar[T]

Radar [u, Turbulence]

Spatial arrangement of Mesospheric Instruments

N

All sky camera [ I ]E

ErwinE

[u, I]EE

E

E

SATI [ T, I]

X

Lidar[T]

Radar [u, Turbulence]

Spatial arrangement of Mesospheric Instruments

N

Horizon


Spectral Airglow Temperature Imager

1) SATI Configuration - Projection onto sky Conical mirror - Spatial spectral scanning Interference filter - Imager CCD camera

2) Measurements - O2 (0-1) atmospheric band - OH (6-2) Meinel band

Young-Min Cho


All-Sky Imager

M.J. TaylorD. Veselinovic

KEO Scientific


ERWIN II


Radar Winds – January 2007

C. Meek


Preliminary Results


SKIYMET MWR at Eureka and MFR at Saskatoon(Manson & Meek)

SemeDiurnal

Diurnal

From Manson & Meek


Diurnal Tidal Signatures in CMAM Latitude and zonal wave number cross section at 95 km

zonal wave number

Negative: eastward

positive: westward

J. Du


CMAM Annual Cycle of Diurnal Tidal Amplitude


Vortex Structure

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

(T. Chshyolkova)


Eureka Monthly Mean U and T

CMAM Zonal Wind CMAM T

MIPAS 2002 T AURA MLS 2006 TD. Wang


Scientific Studies


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

.


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

.


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.


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.


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


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.


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)

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