This document discusses ensuring marine observations are fit for purpose. It notes the Bureau collects over 2 million marine observations per year. Marine observations are crucial for numerous applications including weather forecasting, climate modeling, and informed decision making. The Bureau uses techniques like observing system experiments and forecast sensitivity to observations to evaluate how well observations improve forecasts and determine which observation types have the most impact. Preliminary results found buoys and satellite temperature and humidity profiles significantly improve forecasts. Going forward the Bureau plans to apply these techniques to upgraded forecast models to guide network planning and data assimilation research.

1. Fit for Purpose Marine Observations
Boris Kelly-Gerreyn, Chris Tingwell

2. Bringing the RIGHT marine observations to users
Boris Kelly-Gerreyn, Chris Tingwell

3. Bureau's In Situ Marine, Surface and Upper Air Observation Networks
Obs per year
>1 billion in situ observations per year
>2 million in situ marine observations
Contributing to and benefiting from
large-scale national and
international observing efforts

4. Bureau's reliance on marine observationsNo.ofservicesreliantontheobservation

5. Observations underpin Environmental
Intelligence
• Automatic weather stations
• Weather balloons
• Radars
• Wind profilers
• Satellites
• Drifting buoys
• Tide gauges
• River height gauges
• …
NWP
Forecasters
Forecasts
Warnings
Seasonal
Prediction
Informed Decision Making based on Environmental Intelligence
Observing Networks
Climate
But how do we know that these
observations are fit for purpose ?
NWP
Ocean Model
(OceanMAPS)

6. Numerical Weather Prediction (NWP)
is an initial value problem
NOW
initial condition
F = ma
FUTURE
forecast
The role of data assimilation in NWP is to
specify the initial condition as accurately as possible.

7. Bureau’s NWP = ACCESS NWP Suites
Regional
(11km grid)
Global (25km grid)
7
City
1.5 km
ACCESS (Australian Community
Climate and Earth System
Simulator).
Currently upgrading by end-of-
year.
TC
Global ACCESS assimilates
~126,000 obs per 6hr cycle
Of which Marine :
Drifting buoys
Moored buoys
Ship weather
Based on UKMO Unified Model

8. Assessing the impact of observations in
NWP
• Observing System Experiments (OSE)
• Observing System Experiments (OSSE)
• Forecast Sensitivity to Observations (FSO)

9. The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
OSE example: 1a. Forecast rainfall – no satellite data
Gaps in
obs. data
NWP RAINFALL OBS RAINFALL

10. The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
OSE example: 1b. Forecast rainfall with satellite data
NWP RAINFALL OBS RAINFALL

11. Forecast Sensitivity to Observations
Adjoint-based Forecast Sensitivity to Observations (FSO)
Model
Model
Adjoint model
Significant new technique in
which the forecast error
reduction in (say) a 24 hour
forecast due to data
assimilation can be split up
and attributed to each
individual observation.
Over several weeks, the
reduction of forecast error
due to observing systems,
instruments, groups of
observations etc. can be
aggregated and compared.

12. • Advantage: can run in "real-time"
• Assess impact of
– observation types
– Instruments
– networks and sub-networks
– groups of stations etc.
• A caution:
– Only impact of an observation amongst all other observations;
– not effect of removing an observation, or group of observations, or an
observing system.
Forecast Sensitivity to Observations

13. Preliminary FSO results in ACCESS NWP
J. Lee and P. Gregory, 2013.
Observation counts
Forecast impact
per OBS type
Number of
observations
for each OBS type
Forecast impact
per observation
Buoys
Sat profiles (T,H)

14. Bureau Plans
• Apply to upgraded operational global ACCESS NWP suite.
• Assist in Bureau network planning activities
• Guide data assimilation R&D
• Retrospectives to examine observation impacts in particular
periods of interest. e.g. TC Yasi
• Extend system to higher resolution, limited domain ACCESS
systems.

15. Fit for Purpose Marine Observations
• Ocean modelling applications (building
on GODAEoceanview)
• Coupled ocean-atmosphere NWP
• We are not alone : KMA, ECMWF, NASA,
UKMO
• More partnering and ideas very welcome