The Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments

Transcription

1 The Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments Ankie Piters, KNMI and CINDI Organisation Team

2 Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments Main objectives: June-July 2009, Cabauw, The Netherlands intercompare NO 2 measuring instruments that can be used for validation of tropospheric NO 2 from satellites give estimate of accuracy of NO 2 tropospheric columns and profiles for different atmospheric conditions (clouds/aerosols) and viewing geometries give recommendations for harmonization / standardization of instruments settings and retrieval algorithms Secondary objectives: study effect of horizontal distribution within satellite pixels intercompare other tropospheric measurements, like aerosol, O 3, HCHO, CHOCHO, SO 2, BrO, H 2 O, HONO

3 NDACC UV-Vis WG participating instruments black: MAXDOAS International Context NDACC UV-Vis working group extend to tropospheric products CEOS-WGCV Atmospheric Composition Subgroup long-term ground-truth data sets GEOMON (FP6) WP 2.3 integrate ground-based and satellite measurements ACCENT (FP6) AT2 develop strategies for validation of tropospheric products

4 CINDI participants and instruments 32 instruments for NO 2 21 MAXDOAS-like instruments 4 zenith looking instruments 1 NO 2 lidar 1 NO 2 sonde 5 in-situ instruments other instruments aerosol instruments (in-situ + profile) ozone sondes tropospheric ozone lidar meteorological instruments

5 The site

6 weather conditions Better-than-expected conditions (sunnier, dryer) hours of sunshine, summer 2009 sum: 691 h (48%), normal: 575 h (39%) June July August 22 out of 42 days with satellite overpass data (cloud fraction small enough) from OMI, GOME-2 and SCIAMACHY campaign period

7 pollution conditions CHIMERE simulates substantial NO 2 pollution at Cabauw Factor 6 variability in CHIMERE tropospheric NO 2 columns Note: less NO 2 on clear days related to short NO 2 lifetime courtesy: F. Boersma, KNMI

8 Campaign part 1: semi-blind intercomparison period: June Semi-blind : referee knows who is who in plots Fixed azimuth direction for all instruments Fixed elevation angle sequence for MAXDOAS-like instruments Fixed DOAS settings, wavelength ranges etc

9 courtesy: H. Roscoe, NERC Slant column densities of NO 2 and O 4 agree within 10-20%

10 Campaign part 2: other studies a) Measuring simultaneously at different viewing directions to study the effect of horizontal gradients for satellite validation 328 o 287 o 66 o 253 o 187 o

11 Campaign part 2: other studies b) Measuring in the same azimuth direction from different altitude levels to study the effect of altitude on the retrievals

12 Campaign part 2: other studies c) Measuring from a distance towards the tower to validate with the in-situ sensors at different latitude levels courtesy: D. Swart, RIVM

13 Campaign part 2: other studies d) Mobile measurements to study horizontal gradients for satellite validation courtesy: T. wagner, MPI Mainz

14 more first results

15 in-situ instruments molybdenum converter courtesy: D. Swart, RIVM Blue-Light Converters compare well Molybdenum Converter has large deviations deviation between surface in-situ and 200 m in-situ gives information on boundary layer mixing

16 comparing with in-situ SAOZ partial columns: NO 2 column (top of tower) NO 2 column (surface) MAXDOAS ground level values courtesy: A. Griesfeller, CNRS courtesy: F. Wittrock, IUP Bremen

17 NO 2 profile comparison first comparisons sometimes o.k., sometimes not challenge is to identify what causes the differences 25 June 23 June

18 high resolution ozone and aerosol measurements RIVM trop. O 3 lidar: several profiles per day (1-10km) RIVM Raman lidar: aerosol extinction profiles courtesy: A. Apituley, RIVM

19 AOT Aerosol comparisons CIMEL, 440 nm BIRA, 477 nm Jamstec NRT, 477 nm Jamstec re-analysis, 477 nm KNMI, AOT 427 nm Bremen, 477 nm Heidelberg, 477 nm :00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 Time [UT] courtesy: U. Friess, IUP Heidelberg aerosol extinction profiles Altitude [km] Altitude [km] Y Axis Title Altitude [km] BIRA JAMSTEC Heidelberg RIVM Lidar Time [UT]

20 70 HCHO differential Slant Column Densities 30-June-09: Elevation Angle 2deg dscd [molecules/cm2] x BIRA BREMEN HEIDELBERG GIST UTC courtesy: F. Wittrock, IUP Bremen

21 summarising We had a very successful campaign with: many good measurement days good variability in pollution levels plenty of satellite overpasses A large tropospheric data set is collected for NO 2, aerosol, O 3, and other gases Intercomparisons of slant columns, tropospheric columns and profiles are ongoing in several working groups outlook several cooperation papers are anticipated session proposed at EGU, Vienna, 2 7 May 2010: 'New developments in tropospheric profiling techniques'

22 Credits Thanks to all CINDI participants for sharing the data, plots and photos used in this presentation. CINDI has been financed by: participating institutes via national funding ESA, NASA, ACCENT-AT2 in-kind contributions from KNMI and RIVM scientific organisation team: Michel Van Roozendael, Folkard Wittrock, Ankie Piters, Folkert Boersma local organisation team: Ankie Piters, Mark Kroon, Jennifer Hains, Marian Koning-Klein, Annelise du Piesanie