OPERATIONAL ATMOSPHERIC CHEMISTRY MONITORING MISSIONS

‘CAPACITY’ ESA contract no. 17237/03/NL/GS

GEOPHYSICALDATA REQUIREMENTS

Michiel van Weele, KNMI

Final presentation June 2, 2005

Overview Data Requirements

• Objectives and Strategy to Geophysical Data

Requirements

• Relations to IGACO and other available

requirements

• Sampling and coverage; atmospheric domains

• Spatial resolution and revisit time

• Uncertainty

• Measurement Strategy: Ozone Layer and UV

• Measurement Strategy: Air Quality

• Measurement Strategy: Climate

• Geophysical Data Requirements Tables

• Summary

ObjectivesUser Requirements per Theme:

• Ozone Layer and Surface UV Radiation

• Air Quality

• Climate

and per User Type / Application• Protocol Monitoring

• Near-real time data use

• Assessment

Objectives Compile the user requirements per theme / user category and

interpret in terms of a required set of observables per

atmospheric domain

Define a measurement strategy for the optimal combination of

satellite observations, ground-based / in-situ observations and

use of models

Strategy to Data Requirements

• Specify for each parameter the (threshold) resolution and revisit time requirements per atmospheric domain and on the basis of the observed spatial and temporal variability

• Define a measurement strategy the different role of satellite data, ground-based networks and atmospheric models for each theme/user type combination

• Investigate the role of data assimilation for uncertainty requirements, also in relation with the established resolution and revisit time requirements and sampling/coverage

• Define the auxiliary data requirements for the applications.

• Examine and try to understand differences with tabulated data requirements such as IGACO, GMES-GATO/BICEPS, ESA studies (ACECHEM, GeoTrope, Kyoto), Eumetsat paper on Nowcasting, and MTG requirements

Relations to IGACO and other Requirements

• IGACO data requirements have not been specified per theme/user type.

Instead, distinction has been made in a group-1 (existing systems)

and group-2 (next generation systems) set of observables

• IGACO has four themes, CAPACITY only three. The fourth theme of

IGACO is the oxidising capacity, which in Capacity has been

integrated in the “assessment” of the three other themes

• IGACO requirements are given on a per species and atmospheric

domain basis, but the rationale behind each of the quantitative

requirements has not been detailed in the IGACO report.

• ACECHEM and GeoTrope are compilations of data requirements for

research missions and exceed operational data requirements

• Eumetsat Nowcasting position paper only contains requirements for

<12 hours ahead

• MTG requirements focus on the geostationary, non-global perspective

Sampling and Coverage Requirements

• The themes (Ozone Layer, Air Quality and Climate) are all of a global nature. The target requirement for satellite observations is to get as close as possible to global coverage with near-contiguous sampling.Ground-based networks should be globally representative.

• For Air Quality additional focus is on the local, regional to continental scale in Europe. Threshold coverage for satellite data and surface networks contributing to Air Quality is Europe, including Turkey and Europe’s coastal waters as well as the closest parts of the North-Atlantic.

• The aim of each component to an integrated system should be to maximize its contribution, the number of independent observations mainly being limited by any of the other data requirements on, e.g., uncertainty, resolution and revisit time.

• The integrated system will allow data gaps in space and time, however only up to a certain extent. This will depend on the application.

Atmospheric domains 

US+M

MS

LS

TTL

US+M

MS

US+M

MS

LS LS

LS LS

FT+UT FT,UT

Tropics

Eq. – 30°

Mid-latitudes30° – 60°

Polar region

60° – Pole

FT FT FT

FT+UT+LS

35 km

20 km

16 km

6 km

12 km

PBL PBL PBL 2 km

80 km

Uncertainty

• The (assumed) uncertainty mainly determines the potential impact of observations in assimilation systems. These requirements are most quantitative and are ‘leading’.

• The uncertainty requirement contains a random component and a systematic component. The latter component can only be established by long-term validation with independent measurements.

• For ground-based and in-situ observations a representation error will contribute significantly to the overall uncertainty. Satellite observations suffer less from this error as long as the resolution is more or less comparable to the model grid size.

• Large numbers of independent observations from prolonged data sets with stable retrievals and limited instrumental drift will help to better characterize random and systematic components (=> mission lifetime)

• Spatio-temporal variations in (current) model uncertainties have not been taken into account. Model uncertainties are often related to intermittent processes and unpredictable events, which are often difficult to assign to certain locations and time periods and can not easily be used to relax requirements.

Spatial Resolution and Revisit Time

• Typically the resolution and revisit time requirements are determined by the known variability of the observable in space and time in the different atmospheric domains. Ultimate threshold is to observe ‘some’ of the variability.

• The horizontal resolution should be typically a factor 2-3 smaller than the error correlation length (ECL) used in the assimilation of the observable. The error correlation length is typically a function of altitude and determined by physical processes. The ECL decreases from several 100 km’s in the middle stratosphere to tens of kilometers in the troposphere and even smaller in the PBL.

• Vertical resolution requirements are related to the observed vertical gradients in the atmosphere. Requirements are most stringent in the UTLS and PBL and much less in the free troposphere and middle stratosphere and mesosphere.

• In principle, the revisit time requirements can also be based on required update frequencies from assimilation studies on anomaly correlations. These correlations however mainly depend on the predictability of the meteorology. Revisit time requirements are most stringent in the PBL.

Data Requirements per Theme and User Category

Theme A: Ozone Layer and Surface UV RadiationA1. Protocol MonitoringA2. Near-real time data useA3. Assessment

Theme B: Air QualityB1. Protocol MonitoringB2. Near-real time data useB3. Assessment

Theme C: ClimateC1. Protocol MonitoringC2. Near-real time data useC3. Assessment

Measurement Strategy A1O3/UV Protocol Monitoring

Role of Satellite measurements

Monitoring of the global total ozone spatial distribution (<3% uncertainty for individual measurements)

Contribution to the monitoring of surface UV radiation by provision of information on total ozone, solar irradiance, surface albedo, and aerosol optical depth and absorption

Role of Surface network

Trends in concentrations of regulated ozone depleting substances (ODS) Detection of ODS emissions and their trends Trend in Surface UV and the attribution of UV changes to ozone layer

changes Validation of the satellite data Weekly surface/column observations (O3, ODS) by representative surface

networks

Auxiliary dataMeteorology from NWP centers including surface data (dynamics, clouds, snow

cover)

Measurement Strategy A2O3/UV Near-real time data use

Role of Satellite Measurements

Forecasting of the Ozone layer and surface UV; Feed polar ozone reports Better representation of stratospheric transport, chemistry and radiation

in NWP to improve (medium range) weather forecasts and stratospheric near-real time monitoring, also by improving retrievals of temperature => stratospheric distribution of major greenhouse gases (CO2, H2O, O3, CH4, N2O) and aerosols

Further: tracers (B-D circulation, ST exchange), PSCs

Role of surface network and in-situ operational measurements

NRT validation of the satellite measurements Ozone/ radiosondes: NRT delivery of O3, H2O, p, T, wind NRT delivery of (UTLS) aircraft observations of O3, H2O, CO, HNO3, HCl

Auxilary dataMeteorological forecast from NWP centers including surface data (dynamics,

clouds, sunshine duration, snow cover)

Measurement Strategy A3O3/UV Assessment

Role of Satellite measurements

State of ozone layer and its evolution in time; role of dynamics, radiation, and chemistry

Changes in surface UV radiation globally, per location Distribution and trends in ODS and reservoir species The role of PSCs and of denitrification The role of volcanic eruptions (SO2, aerosol, aerosol type) Short-lived species can typically be derived from long-lived species

given that the chemistry is sufficiently understood (some exception: NO2, ClO etc)

Role of Surface network

Validation of the satellite measurements Surface UV radiation trend monitoring and attribution Concentration monitoring ODS; detection of ODS emissions

Auxiliary datameteorology from NWP centers including surface data (dynamics,

clouds, sunshine duration, snow cover)

O3 / Surface UV Radiation: Satellite Data

Observable User(s) Domain(s)

O3 A1, A2, A3 Stratosphere, Troposphere

UV solar spectrum A1, A2, A3 Top-of-Atmosphere

UV aerosol optical depth A1, A2, A3Troposphere

UV aerosol absorption optical depth A1, A2, A3Troposphere

Spectral UV surface albedo A1, A2, A3 Surface

H2O A2, A3 StratosphereN2O A2, A3 StratosphereCH4 A2, A3 StratosphereCO2 A2, A3 StratosphereHNO3 A2, A3 StratosphereVolcanic aerosol A2, A3 Stratosphere

CFC-11 A3 StratosphereCFC-12 A3 StratosphereHCFC-22 A3 StratosphereClO A3 StratosphereBrO A3 StratosphereSO2 A3 StratosphereAerosol surface density A3 StratospherePSCs A3 StratosphereHCl A3 StratosphereClONO2 A3 StratosphereCH3Cl A3 StratosphereHBr A3 StratosphereBrONO2 A3 StratosphereCH3Br A3 Stratosphere

Measurement Strategy B1Air Quality Protocol

Monitoring

Role of Satellite Measurements

Interpolation of surface networks in the PBL Boundary conditions for regional AQ models and tropospheric

background (long-range transport) Application to inverse modeling of surface emissions (aerosols, NO2,

SO2, CO, CH2O). Formaldehyde is related to VOC emissions

Role of Surface Networks

EU Framework Directives (surface concentrations) National Emission Ceilings (concentration monitoring to derive

emissions) Gothenburg protocol on ground-level ozone Ship emissions (operational ship monitoring coastal waters) A representative network for surface concentrations and emissions in

Europe Satellite and model validation, also by boundary layer profiling

(LIDARS, Towers)

Auxiliary dataMeteorology from NWP Centers including surface data (dynamics, clouds,

surface characterization)Emission inventories

Measurement Strategy B2Air Quality Near-real time data

use

Role of Satellite Measurements

Interpolation of surface network in PBL Plume transport and plume dispersion on local, regional, continental

and global scale Boundary conditions to regional AQ models and tropospheric

background levels Early warnings on hazards and unpredictable events

Role of Surface Networks

Local Air Quality monitoring of surface levels Constraints on satellite-derived aerosol types and VOC emissions

from HCHO NRT ozone sonde data for ozone and relative humidity profiles CH4 trend monitoring

Auxiliary dataForecast meteorology from NWP centers including NRT surface /

vegetation dataEmission inventories

Measurement Strategy B3Air Quality Assessment

Role of Satellite Measurements

Global-scale oxidizing capacity components and their evolution in time (O3, CO, H2O, NOx, CH4, CH2O, UV, aerosols)

Long-range transport of pollutants; tropospheric background levels Interpolation of data from surface networks input to inverse modeling of surface emissions (CO, NOx, SO2,

CH2O) Isotopes of CO to distinguish between emission types

Role of Surface network

Assessment of surface concentrations and boundary layer pollution over Europe

Concentration monitoring to derive emissions on national levels HNO3, N2O5(at night) and org. nitrates: reservoir species to

constrain acid deposition and N budget Validation of satellite observations (including sondes, lidars, towers)

Auxilary dataMeteorology from NWP centers including surface characterisationEmission inventories

Air Quality: Satellite Data

Observable User(s) Domain(s)

O3 B1, B2, B3 PBL/TroposphereNO2 B1, B2, B3 PBL/TroposphereCO B1, B2, B3 PBL/TroposphereSO2 B1, B2, B3 PBL/TroposphereCH2O B1, B2, B3 PBL/TroposphereAerosol OD B1, B2, B3 PBL/TroposphereAerosol Type B1, B2, B3 PBL/TroposphereH2O B2, B3 PBL/TroposphereHNO3 B2, B3 PBL/TroposphereN2O5 B2, B3 PBL/TropospherePAN / Org. nitrates B2, B3 PBL/TroposphereSurface UV albedo B2, B3 Surface

Measurement Strategy C1Climate Protocol Monitoring

Role of Satellite Measurements

Concentration monitoring for inverse modeling of emissions of CH4, CO2, CO and NO2

Global concentration distributions of the mentioned gases, O3 and aerosols

Role of Surface network

Greenhouse gases trend monitoring (CO2, CH4, N2O, SF6, CF4, HFCs Weekly surface concentrations and total columns from a representative

network. Validation of satellite measurements Concentration monitoring for inverse modeling of surface emissions of

CH4, CO2, CO and NO2 Tropospheric O3: sondes, lidar and surface data; Tropospheric aerosol optical depth and aerosol absorption optical depth Trend monitoring for ozone depleting substances ODS with climate

forcing: (H)CFCs.

Auxiliary dataMeteorology from NWP centers including surface dataEmission inventories and estimates on sinks

Measurement Strategy C2Climate Near-real time data

use

Role of Satellite Measurements

For use in assimilation at NWP centers to improve on stratospheric elements

H2O, O3, stratospheric tracers, and information on aerosols and cirrus Climate monitoring (delivery time ~weeks – months) Validation of climate and NWP models (present-day climate

reconstructions)

Role of Surface network

NRT validation of satellite observations Evolution of long-lived greenhouse gases In-situ observations in the PBL of CO2 NRT delivery of ozone sonde / Lidar data: O3, H2O

Auxiliary dataForecast meteorology from NWP centers including surface data

Measurement Strategy C3Climate Assessment

Role of Satellite Measurements

Assessment radiative forcing and its changes over time, including volcanic eruptions and solar cycle: GHGs, aerosol OD, aerosol absorption, SO2, cirrus)

Assessment of stratospheric H2O budget and H2O trend monitoring The role of the ozone layer evolution on climate change: CFCs, Cly, ClO,

HNO3 The role of the oxidizing capacity of the troposphere for climate change

(CH4, CO, O3, H2O, NOx, UV) The role of a changing B-D circulation on climate change: tracers Concentration monitoring for inverse modeling of GHG & precursor

emissions

Role of Surface network

Validation of satellite observations Ozone sonde/LIDAR network for trends in strat. profiles of long-lived gases Radiosonde/GPS network for H2O and T Aerosol network UTLS operational aircraft observations of O3, H2O, CO, NOx

Auxiliary dataMeteorology from ECMWF analyses, including surface data

Climate: Satellite Data

Observable User(s) Domain(s)

CH4 C1 PBL, TroposphereCO2 C1 PBL, TroposphereCO C1 PBL, TroposphereNO2 C1 PBL, TroposphereO3 C1 PBL, TroposphereAerosol OD C1 PBL, TroposphereAerosol absorption OD C1 PBL, Troposphere

H2O C2, C3 Troposphere, StratosphereO3 C2, C3 Troposphere, StratosphereCH4 C2, C3 StratosphereCO2 C2, C3 StratosphereN2O C2, C3 StratosphereAerosol optical properties C2, C3 StratosphereCirrus optical properties C2, C3 TroposphereHNO3 C3 Troposphere, StratosphereNO2 C3 StratosphereSF6 C3 StratosphereCl compounds C3 StratosphereN2O5 C3 StratospherePAN C3 TroposphereCO, HCs, CH2O,H2O2 C3 Troposphere

Data Requirements Table Format

A1S:Ozone Layer; Protocol Monitoring; Satellite data

• Data product + Driver

• Height Range(s)

• Hor. Resolution (target/threshold)

• Vert. Resolution (target/threshold)

• Revisit time (target /threshold)

• Uncertainty (threshold)+ Similar Tables for A1-G, A2-S, A2-G, ….C3-S, C3-G (18 Tables in total)

Summary

• This work has drawn from several earlier requirement studies, but it has never been done before in such a comprehensive way with focus on atmospheric composition and for operational applications

• Geophysical Data Requirements have been tabulated per theme and within each theme per user type

• Per data product and product type (column, profile) resolution, revisit time and uncertainty have been tabulated, for each atmospheric domain

• Based on the definition of ‘drivers’ per application a measurement strategy has been proposed for satellites, ground-based/in-situ data and auxiliary data, including models

• The tables, traceable to the user requirements, served as input for the analysis of existing/planned missions and networks, and for the definition of instrument requirements for new mission concepts