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SIRTA Cloud and Radiation Observatory

SIRTA Cloud and Radiation Observatory. Institut Pierre Simon Laplace. Algorithms.

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SIRTA Cloud and Radiation Observatory

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  1. SIRTA Cloud and Radiation Observatory Institut Pierre Simon Laplace Algorithms M. Haeffelin, A. Armstrong, L. Barthès, O. Bock, C. Boitel, D. Bouniol, M. Chiriaco, J. Delanoe, P. Drobinski, J-L. Dufresne, C. Flamant, M. Grall, F. Hourdin, F. Lapouge, Y. Lemaître, A. Mathieu, Y. Morille, V. Noel, J. Pelon, C. Pietras, A. Protat, B. Romand, G. Scialom, R. Vautard, Y. Wanherdrick Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  2. Data Products Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  3. Lidar Data Products Cloud and aerosol vertical structure • Wavelet transform method: • Search for high correlation between a wavelet and the lidar signal • Mexican hat for particle layers in the free troposphere • Step function for boundary layer • Cloud / aerosol separation based on PR2 peak-to-base ratio • Distinction between true noise (no more photons) and apparent noise (no more scatterers) Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  4. Lidar Data Products • L0: • Lidar back-scattered power • L1: • Quality flag • Monitoring noise • L2: • Atmospheric Mask (Clouds, aerosols, Boundary layer, Particle-free zone, Noise • Cloud thermodynamic phase • Cloud and aerosol layer optical depth • L3: • Time and layer -average data Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  5. Radar-Lidar Cloud Products Combine Reading classification with LNA classification Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  6. Cloud Product Dataset Analysis • Processed LNA Lidar data: 10/2002 - 09/2004 • Cloud, aerosol mask • Time averaged data 20040830 7.0 10005 11655 100 20040830 8.0 01515 01995 100 10170 11700 083 20040830 9.0 10710 11790 100 20040830 10.0 01620 01995 030 10545 11865 100 20040830 11.0 01815 02220 100 09435 12000 100 20040830 12.0 01650 02325 100 09150 12150 100 20040830 13.0 02055 02490 086 09990 12135 100 20040830 14.0 02085 02550 100 09675 12060 095 20040830 15.0 01875 02760 100 09390 11565 070 20040830 17.0 08550 11715 100 Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  7. Cloud Product Dataset Analysis Frequency of occurrence of cloud fraction and vertical distribution of cloud layers Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin Palaiseau 10/2002-09/2004 LNA Lidar

  8. Cloud Product Dataset Analysis Frequency of occurrence of single and multiple cloud layers Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin Palaiseau 10/2002-09/2004 LNA Lidar

  9. Cloud Product Dataset Analysis Frequency of occurrence of cloud thickness and vertical distribution Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin Palaiseau 10/2002-09/2004 LNA Lidar

  10. Cloud Product Dataset Analysis Relative occurrence of cloud altitude (monthly variations) Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin Palaiseau 10/2002-09/2004 LNA Lidar

  11. Cloud Product Dataset Analysis Relative occurrence of cloud altitude (seasonal variations) Vertical Extent of Clouds Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin Palaiseau 10/2002-09/2004 LNA Lidar

  12. Cloud Product Dataset Analysis Relative occurrence of cloud-base altitude (seasonal variations) Occurrence of Cloud Base Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin Palaiseau 10/2002-09/2004 LNA Lidar

  13. Lidar Data Products • Cloud thermodynamic phase • Based on lidar depolarization ratio + b threshold • Requires normalization in particle-free zone (2.74%) Normalization problem Ice water Mixed phase Liquid water Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  14. Lidar Data Products Cloud optical depth Molecular Integration method:t = ∫ a(z)dz Integrated extinction = power loss between theoretical molecular return below the cloud and molecular return above the cloud Particle Integration method: t = LReff ∫ (R(z)-1)bm(z)dz where R(z)=(bm(z)+bc(z))/bm(z) LReff prescribed: 18 sr LReffopt derived from MI method Cadet et al. 2004 Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  15. Lidar Data Products Cloud optical depth Cadet et al. 2004 Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  16. Radiative Flux Station • Operations: • 18 months of Global SW + LW • SW Direct + Diffuse missing 12/03-02/04 SW LW Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  17. Radiative Flux Dataset Analysis SW Direct SW Diffuse SW Global LW Down May 2004 Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

  18. Radiative Flux Dataset Analysis Shortwave radiative impact of cloud layers Clear-sky reference from F = a cos(q)b Single-layer high-altitude clouds Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin May 2004

  19. Perspectives Institutes and programs supporting SIRTA: • Produce 2-year radar-lidar L3 products • Pursue analysis of vertical structure • Pursue developments of lidar-only retrievals and combination • Develop clear-sky flux and radiative forcing products, and analyse in relation to the cloud data base Cloudnet meeting 18-19 Oct 2004 - Martial Haeffelin

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