Polar Communications & Weather (PCW) Mission
Louis Garand and Alexander P. TrishchenkoEnvironment CanadaGuennadi Kroupnik, Canadian Space AgencyTHORPEX DAOS Working Group Third MeetingMontreal, July 8-9, 2010
Motivation for Arctic Observations
• A rapidly changing environmentclimate change amplified and accelerated in polar regionsrapidly diminishing ice coverchanging snow, permafrost and vegetation cover
• A gap in global observation systemssparse in-situ networksgeostationary observing systems not suitable >55
• High meteorological and climate significanceimpacts on global weather and climate predictionsignificant region for air pollution, volcanic ash transport
• Increasing economic activity resource exploration and development increased marine and air trafficneed for operational information infrastructure to support operations, safety, and regulation
• Active region of space weather phenomena
Imagery needs for polar regions latitudes 55-90
• Not served by GEO• Incomplete from LEO
- Single satellite limitations:* Passages every 90 min* Only partial coverage of circumpolar area
- Multiple satellite compositing limitations:* Discontinuities in time and viewing geometry* Differences in channel characteristics
Ideally, we want GEO-like imagery over the poles
Background on Molniya (HEO) concept
• Russia: - Used extensively for communications and classified missions - Mission including Earth observation planned: “Arctica”
• United States- Concept for Earth observation first proposed by Kidder and Vonder Haar
(1990)- NASA/Goddard proposed a mission in 2004-2005. Main focus was on high
latitude winds. Main payload was a 6-channel imager. Stopped at Phase A level.
• Canada- CSA initiated a satcom/EO mission concept study in 2005- Saw the opportunity to take relay from NASA in 2006- Completed a Phase 0 in November 2008- Phase A started July 2009, “ended” July 2010- Currently actively working to promote mission to Phase B
Polar Communications and Weather Mission - Objectives
1. Reliable communications and navigation servicesin the high latitudes (North of 70º) to ensure:
SecuritySustainable DevelopmentSupport to Northern CommunitiesSafety of the Air and Marine NavigationArctic Science
2. High temporal/spatial resolution meteorologicaldata above 50º N in support of:
Numerical Weather Prediction (short to medium range)Environmental monitoring, emergency responseClimate monitoring
3. Space Weather Monitoring
• Canadian-led mission with international partnerships• Canadian contribution to WMO space-based observing system• data policy consistent with Resolution 40 (free access)
Areas of Interest
Meteorological Coverage Requirement (50ºN)
Meteorological Coverage Goal (45ºN)
Communications Coverage Requirement(Canadian requirement only shown)
Meteo requirement pertains to the entire circumpolar domain
2-sat constellation in Molniya Orbit = continuous views over one pole
2 satellites to providecontinuous GEO-likeimagery 50-90 N15 min refresh
0.5-1 km VIS2 km IR
12-h period63.4 deg. inclination
Apogee: ~39,500 kmPerigee: ~600 km
2-way, 24/7 high data Rate communications (up to 12 Mb/sec)Ka-band
Payloads and Mission
• Primary Payloads (Core mission):– Ka-band and X–band 2-way High Data Rate communications
– Imaging Spectroradiometer(20 channels, 0.5-1 km VIS, 2 km IR)
– Space weather suite of instruments
• Secondary Payloads (Enhanced mission)– Additional mass and power capacity may permit secondary payloads
(under evaluation); e.g.;
GNSS augmentation, Air Traffic ManagementScience instruments: Broadband radiometer, Aurora Imager, Atmospheric composition instrument (UV-NIR), Fourier Transform spectrometer (IR, similar to IASI)Technology demonstration: Software defined radio, V-band communications
• MissionInitial 5-7 year design life, with recurring missions
Preliminary Spacecraft Concept
Mass: up to 2000 kgPower: up to 4000 W Pointing Knowledge: 7.6 arcsecPointing Control: 55.1 arcsec
Ka-band telecom antennas
Meteo instrument aperture
Preliminary Services Concept
Ka-band downlink to gateway station
Ka-band , 2-way telecom beams (4)(for Canadian area of interest)
Imaging area for meteo instrument
Applications and Products (Meteo) 1/2
• Level -1 and Level-2 product requirements defined in User Requirements Document
Near real time
• Atmospheric motion vectors (AMVs) from sequences of images
• Nowcasting applications: severe weather, visibility (fog), icing in support of air and marine traffic, stability index, turbulence
• Direct assimilation into NWP - low to mid tropospheric sensitive IR channels
• Smoke (fires), dust, aerosols in support of air quality models and environmental prediction
• Volcanic ash detection and tracking
• Surface temperature, boundary layer inversions
Atmospheric Motion Wind Vectors:PCW to fill the Arctic gap
MODIS polar winds have limited coverage and will not be availableat end of satellite life
Volcanic Ash detection and tracking: PCW would serve the whole Arctic
Volcanic Ash Advisory Centers (VACC) - areas of responsibility
Invaluable data to Dorval, London, Moscow and Anchorage VACCs.Addition of 0.87 micron channel expected to largely reduce false alarms. Major improvement over LEO (AVHRR).
Applications and Products (Meteo) 2/2
Other products
• Surface analyses– ice, snow, ocean, vegetation and surface characteristics – emissivity, albedo, leaf area index (LAI), fraction of absorbed
photosynthetically active radiation (fAPAR)
• Total column ozone
• Cloud parameters– height, fraction, temperature, emissivity, phase, effective particle size
• Contribute to satellite-derived Essential Climate Variables (ECVs)
Key instrument: Advanced imager similar to GOES-R ABI (2015) or MTG (2016)
Wavelength (microns)
Heritage Goal spatial resolution
(km)
Main applications
0.45-0.49 ABI-01 1 Surface
0.59-0.69 ABI-02 0.5 Wind, clouds
0.85-0.891.04-1.06
ABI-03SGL1 SW1
0.51
Wind, aerosols, vegetationSnow grain
1.37-1.39 ABI-04 1 Cirrus
1.58-1.64 ABI-05 1 Snow-cloud distinction
2.22-2.28 ABI-06 2 Cloud phase
3.80-4.00 ABI-07 2 fog/ fire detection, Ice/cloud separation, wind
5.77-6.60 ABI-08 2 Wind, humidity
6.75-7.15 ABI-09 2 Wind, humidity
7.24-7.44 ABI-10 2 Wind, humidity
8.30-8.70 ABI-11 2 Total water
9.42-9.80 ABI-12 2 Total ozone
10.1-10.6 ABI-13 2 Cloud, surface
10.8-11.6 ABI-14 2 Cloud, SST, ash
11.8-12.8 ABI-15 2 Ash, SST
13.0-13.6 ABI-16 2 Cloud height
13.5-13.8 MODIS-34 2 Cloud height
13.8-14.1 MODIS-35 2 Cloud height
14.1-14.4 MODIS-36 2 Cloud height
PCW Imager Requirement: 20 channels
Advanced imager similar to:• GOES-R ABI (2015) or• MTG (2016)
Mission Development Structure in Phase A
LeadCanadian Space Agency
(CSA)
Users and Science TeamEnvironment Canada (EC),
Dept. of National Defense (DND),Natural Resources Canada,
Canadian Coast Guard,Transport Canada, NavCanada,
Dept. of Indian and Northern Affairs,Gov. of Nunavut
And other gov. agenciesInternational Section of U&ST
Industrial TeamMDA, Com Dev,
ABB Bomem, Bristol Aerospace,
SED
Status and Major Milestones
Approved and Funded• Phase 0 completed: September 2008• Phase A contract awarded: July 2009• Phase A Major Milestones
– Technology Readiness Assessment Review: October 2009– Critical Technologies Development procurement: February 2009– Mission Requirements Review: February 25, 2010– Preliminary System Requirements Review: June 2010– Phase A contract close out: July 2010
• Critical Technologies development contracts award: April 2010
Approval and Funding Still Required• Phase B/C/D contract award: February 2011• Launch of Satellite 1: August 2016• Launch of Satellite 2: November 2016• Beginning of operations: January 2017
International Engagement
• NOAA, NASA, EUMETSAT, FMI, SHMI, ESA, ECMWF participation in International section of User & Science Team
• FMI: strong commitment
• NOAA– Contributions to PCW to be explored through EC-NOAA MOU, and
Canada-US Agreement on space technology.
• Russia Arktica Mission– liaison through WMO Focus Group on HEO and bi-laterally– agreement in principle to coordinated missions – e.g., orbital
configuration, imaging frequency, etc
Example User & Science Team activities
• End-to-end simulator of PCW imager– Level 0 (raw) to Level 1c
(calibrated/navigated mapped on a fixed polar stereographic grid)
• Development of fast radiative transfer models
• Observing simulation experiments– e.g., evaluate impact of PCW satellite winds on forecasts
• Ground segment, data acquisition/distribution scenarios– define requirements for future PCW data processing center
• Development of partnerships– science/algorithm support, instruments, other….
24-h ground track, 15 min positions Useable view of polar area +- 4h to apogee
-18 0 -1 50 -12 0 -90 -6 0 -30 0 3 0 60 9 0 12 0 1 50 18 0-9 0
-6 0
-3 0
0
3 0
6 0
9 0
1 5 -m in in te rva ls
Latit
ude
[deg
]
L o n g itu d e [d e g ]
M o ln i ya o rb i t w ith 1 2 -h r p e r io d
Location of apogees and coverage for PCW system
950W
50W1750E
850ELocation of apogees was selected to maximize land mass observations at small viewing zenith angles (VZA), i.e. looking close to nadir over land
Properties of apogees: • Four fixed positions• Occur at same local time• Clockwise succession
Travelling with PCW
Temporal Sequence of Earth Views-4hrs
+4hrs
-3hrs
+3hrs
0hrs
23.70 x 23.70 19.20 x 19.20
15.70 x15.70
31,400 km
24,000 km
39,850 km
24-h animation 1 satellite, 11µµµµm
From 35 km Model output15 min
Simulation of PCW Imagery from 10 km model output, 7.3 micron, 24-h, 15 min
24-h Animation VIS ch-2, 15 min
Examples of Level-2 product requirements
Data productHorizontal
resolution
AccuracyProduction
repeat cycle
Product Latency
Wind Low (> 700 hPa) 30/200 km 2.0/5.0 m/s
1.0/3.0 h 0.5/1.5 h
Wind Mid (400-700 hPa)
30/200 km 2.5/5.5 m/s
1.0/3.0 h 0.5/1.5 h
Wind Upper (<400 hPa)
30/200 km 3.5/7.5 m/s
1.0/3.0 h 0.5/1.5 h
Sea surface temperature
10/50 km 0.5/1.0 K 1.0/3.0 h 1.0/3.0 h
Land surface temperature
5/25 km 1.0/2.5 K 0.25/2.0 h 0.25/1.0 h
Total ozone 25/100 km 10/50 DU 0.25/2.0 h 1.0/3.0 h
Cloud cover 5/100 km 5/10 % 0.25/1.0 h 0.1/1.0 h
Cloud top height 5/100 km 0.2/0.9 km 0.25/1.0 h 0.1/1.0 h
Integrated humidity 25/100 km 10/20 % 0.25/1.0 h 0.5/1.0 h
Total aerosol optical depth
15/100 km 10/50 % 1.0/6.0 h 0.5/3.0 h
Preliminary surface Essential Climate Variables (ECVs) from PCW
Parameter Spatial resolution Temporal resolution
Product accuracy
Geolocation accuracy
Surface Albedo/BRDF 1-2km 1day 5% (1%) 1/3 FOV
Land cover (incl. vegetation type) 1-2km (Mod-res) 1yr 15% 1/3 FOV
Leaf Area Index (LAI) 1-2 km 1day 0.5 (1/3 FOV)
Fraction of Absorbed Photo-synthetically Active Radiation (fAPAR)
1-2km 1day 0.05 (1/3 FOV)
Snow cover 1-2km 1day 5% 1/3 FOV
Fire disturbance (including FRP) 1-2km 1day(<1hr) 5%(2-5K) 1/3 FOV
NDVI (other VIs)* 0.5-1km 1day 5% 1/3 FOV
Vegetation Fraction* 0.5-1km 1day 5% 1/3 FOV
Land Surface Temperature* 2-4km ~1hr 2.5-5K 1/3FOV
Land Surface Emissivity* 2-4km 1day 5% 1/3FOV
NRCan to be responsible for production of ECVs
Improved clear-sky statisticsdue to high temporal frequency
(1-day model data for July 1, 2008)Start: July 1, 2008 3:00UT
Initial clear-sky mask
clear
cloud
Accumulated clear-sky mask after 24hrs
Daily mean cloud fraction :
Mean cloud fraction after clear-sky compositing :(every 15min over 24hrs)
69% (64%)
34% (32%)
(500N-900N)
Angular sampling from Molniya HEO
20 40 60 80 1000
30
60
90
Longitude 950W 500N
600N
700N 800N
VZ
A [d
eg]
SZA [deg]
0
30
60
90
0
30
60
90
120
150
180
210
240
270
300
330
0
30
60
90
Longitude 950W500N600N700N 800N
VZ
A [d
eg]
Rel Azimuth AngleSZA-VZA sampling VZA-RAZ sampling
Orbit precession around direction to the Sun: 1.14deg/day. Complete cycle is ~ 10.5 month (360 deg)Rich angular sampling from HEO Molniya orbit => better observations of angular anisotropy of the Earth radiation field than for polar orbiters and GEOExcellent stereo views 3h from apogee
PCW and Polar Prediction
Major contribution to:
• DA for polar meteorology- AMV’s- high temporal radiance assimilation- surface variables- aerosol, ozone, volcanic ash- possibility of hyperspectral sounding
• Understanding polar processes (clouds, radiation, dynamics of polar lows…)
• Model validation facilitated from instantaneous view over entire circumpolar area
• Climate change monitoring
Mode grid centered on pole, resolution ~10 km desirable
Conclusion
• PCW 2-sat constellation will provide geostationary-like imagery over the entire circumpolar area 50-90.
• High priority for CSA, EC and other federal departments.• Benefits from strong international support, including
WMO. • Represents a new mandate for Canada in Earth
Observations. Major legacy of IPY.
Strong link to THORPEX Polar Project !
