ppt - Atmospheric Sciences

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Atmospheric Science in the “Deep
South” National Science Challenge
Adrian McDonald
University of Canterbury,
Christchurch, New Zealand
The Deep South
The Deep South National Science Challenge is one of ten
key areas for research that the New Zealand
Government identified last year. These challenges are
planned to be the foci for New Zealand research over
the next 10 years.
Objective: To understand the role of the Antarctic and
southern ocean in determining our climate and our
future environment.
The Deep South : Aims
 Increase the knowledge and reduce uncertainty of how the Antarctic
influences the oceanic-climate interfaces in the southern ocean, atmosphere,
and biosphere. This will support the building of models that predict potential
changes to our climate and ocean system and the risks and impacts on our
resources
 Understand the critical role of the Antarctic and the southern ocean on our
social, cultural, and economic wellbeing, and active kaitiakitanga. This will
enable New Zealanders to effectively respond and adapt to change (refer
Glossary for definition of ‘change’) that impacts New Zealand, and sustainably
manage New Zealand’s natural resources accordingly
 Allow New Zealand to take advantage of its unique geographic location to
develop a global hub for Antarctic and southern ocean research, to build
international scientific collaborations that contribute to addressing climate
change issues for research in Antarctic and the southern ocean, and to
leverage benefits from this for New Zealand.
 Make a New Zealand contribution to national and international decisionmaking on global change.
Atmospheric Science in the
“Deep South”
Polar influences on the westerlies:
The Southern Hemisphere
westerly winds play a critical role in the climate of New Zealand and in Southern Ocean
circulation. The strength and latitudinal position of these winds largely determine
temperature and precipitation patterns in many parts of the country. The westerlies are
primarily driven by the north--‐south temperature gradient between the tropics and
Antarctica. This dependence ensures that the westerlies both contribute to, and
respond to circulation in the Southern Ocean, changes in the ozone hole and variations
in cloud and precipitation patterns.
Four main areas of activity:
Climate modelling
Manned research base on Auckland Island
Research Cruise focussed on aerosol and air-sea interactions
(Mike Harvey just discussed in Session 3 so will skip this one)
Atmospheric Remote Sensing above the Southern Ocean
Climate Modelling
(Olaf Morgenstern, Sam Dean, Greg Bodeker,
Peyman Zawar-Reza)
 A hierarchy of models with differing complexity, geographical coverage, and
computational cost will be utilised. This will allow for different modelling approaches to
be used to investigate different aspects of the climate system and potentially reduces
uncertainty.
 NIWA-UKCA: The most comprehensive, and most computationally demanding, model is a
state-of-the-art atmosphere-ocean chemistry-climate model, NIWA-UKCA. This model
simulates changes in the atmosphere-ocean climate system, including the ozone layer, under
increasing greenhouse gas concentrations and decreasing ozone depleting substance
concentrations. Potential studies include an examination of the representation of interactions
between aerosols and clouds in NIWA-UKCA.
 HadGEM3: Due to its complexity, NIWA-UKCA, is limited to relatively small ensemble sizes.
NIWA also operates HadGEM3-A and this model will be used to run larger ensemble
experiments. For the NSC we will construct a large ensemble of HadGEM3-A simulations that
are based on the sea surface temperatures and ozone forcing predicted by NIWA-UKCA.
 ISCM: ISCM is an interactive simple climate model that extends the MAGICC model used in the
IPCC 5th assessment report. This model expands on the MAGICC model by including the two
way interaction between Antarctic stratospheric ozone and the southern high latitude climate
system. We will use energy balance models in combination with ISCM to examine the
interaction between cloud feedbacks and the sea ice albedo effect to examine how clouds
may moderate polar amplification.
 WRF: The Weather Research and Forecasting (WRF) model is used at NIWA and University of
Canterbury to undertake high resolution process studies and by the Meteorological Service of
New Zealand Ltd. (MetService) to dynamically downscale forecasts from global modelling
centres.
Initial Plans: Auckland Island
Sub-Antarctic Base
Macquarie Island
Auckland Island
Auckland Island is South of
New Zealand and almost on a
direct line from Christchurch
to Macquarie Island.
The Auckland Islands are
an archipelago of the New
Zealand sub-antarctic islands
with a combined area of
roughly
625
square
kilometres (240 sq mi). They
lie 465 kilometres (290 mi)
from the South Island port of
Bluff.
Latitudes 50° 30' and 50°
55' S and longitudes 165°
50' and 166° 20' E.
Auckland Island Base
Planned instrumentation on Auckland
Island:
 Ceilometer (Adrian McDonald,
UC)
 X-band
vertically
pointing
weather radar (Geoff Austin,
Auckland University)
 Radiosonde sounding system
(Greg
Bodeker,
Bodeker
Scientific and NZ MetService)
 UAV and Flux tower (Peyman
Zawar-Reza, UC)
 Distributed wireless sensor
network - SNOW WEB (Adrian
McDonald, UC)
SNOW WEB: Future deployment
to Auckland Island?
SNOW WEB is a smart distributed wireless sensor network designed
at UC. It has been designed for easy deployment and provides the
ability to vastly increase the density of atmospheric (wind velocity,
temperature, pressure and humidity) measurements in a region on a
campaign basis. The Figure above shows a previous deployment
around Ross Island in Antarctica and corresponding WRF output.
Atmospheric Remote Sensing
above the Southern Ocean
 Remote sensing is seen as critical in providing large
scale constraints for modelling.
 Three sets of systems will be used extensively:
CloudSat/CALIPSO
WindSat
MISR
Discuss only the latter two here.
WindSat Introduction
(Adrian McDonald, UC)
 WindSat is a polarimetric microwave radiometer satellite. It
operates at the following frequencies :
 10.7, 18.7 and 37.0 GHz with polarizations vertical, horizontal,
+45, -45, left-hand and right-hand circular
 6.8 and 23.8 GHz with polarizations vertical and horizontal
 WindSat uses these measurements to derive the following
quantities:
 sea surface wind speed and direction
 sea surface temperature
 Total column water vapour
 cloud liquid water
 rain rate
SAM regression analysis
 Initial study has focussed on using data from the
WindSat instrument to develop an integrated viewpoint
of variations linked to the Southern Annular Mode
(SAM). This also provides analysis which can be
compared with previous work to test WindSat output.
 Later analysis will aim to combine WindSat with other
instruments to gain synergies (CloudSat/CALIPSO and
MISR).
 To examine the impact of SAM on the WindSat
variables we form anomalies by detrending and deseasonalising the daily WindSat data and then
regressing these anomalies onto a daily SAM index.
 The patterns shown next indicate the change from the
mean that would result from a one-standard deviation
positive SAM anomaly.
WindSat analysis : SAM
regression (one sigma anomaly)
Zonal wind (m/s)
TCWV (%)
Meridional wind (m/s)
Cloud Liquid water (%)
SST(K)
Rain rate (%)
WindSat and ERA-interim
analysis
Initial comparison of the SAM positive anomaly in
meridional wind from WindSat and ERA-interim shows
clear relationships. Given this initial analysis uses different
data periods the relationship is rather good.
WindSat
ERA-interim
WindSat and NVAP-M analysis
Initial comparison of the Total column water vapour SAM
positive anomaly from WindSat and NVAP-M shows clear
relationships. Given this initial analysis uses different data
periods the relationship is rather good.
WindSat
NVAP-M
WindSat cyclone detection
(Adrian McDonald and Alex Schuddeboom, UC)
A positive SAM phase is characterised by anomalously high pressure in the midlatitudes and anomalously low pressures in the latitudes closer to the South Pole.
Initial analysis of the relative vorticity field, derived from WindSat wind speed
and direction data, can be used to identify the position of cyclonic centres for
different SAM phases.
MISR analysis
(Roger Davies, Auckland University)
Planned to examine the MISR wind product
derived from cloud-tracked winds.
Possible synergies with WindSat analysis, that
gives surface winds, with MISR which gives
height-resolved winds.
 Already known that the reanalysis data that
does not ingest MISR winds has biases mainly
over the Southern Ocean.
Conclusions
The “Deep South” NSC aim is to understand the role of the Antarctic
and southern ocean in determining New Zealand climate and New
Zealand future environment.
Four main areas of activity:
 Climate modelling
 Manned research base on Auckland Island
 Research cruise focussed on aerosol and air-sea interactions
 Atmospheric Remote Sensing above the Southern Ocean
Initial remote sensing study described has focussed on using data from
the WindSat instrument to develop an integrated viewpoint of variations
linked to the Southern Annular Mode (SAM) and cyclone distributions.
Potentially useful for identifying synoptic context for cloud regimes.
Acknowledgements
Thanks to the New Zealand Antarctic
Research Institute for partial funding for my
attendance at this meeting.
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