1 / 13

Observations and Models of Boundary-Layer Processes Over Complex Terrain

Observations and Models of Boundary-Layer Processes Over Complex Terrain. What is the planetary boundary layer (PBL)? What are the effects of irregular terrain on the basic PBL structure? How do we observe the PBL over complex terrain? What do models tell us?

saman
Download Presentation

Observations and Models of Boundary-Layer Processes Over Complex Terrain

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Observations and Models of Boundary-Layer Processes Over Complex Terrain • What is the planetary boundary layer (PBL)? • What are the effects of irregular terrain on the basic PBL structure? • How do we observe the PBL over complex terrain? • What do models tell us? • What is our current understanding of the PBL and what are the outstanding problems to be addressed?

  2. Modeling the PBL Over Complex TerrainIssues and Applications

  3. Planetary boundary layer 1 km Height (m) • Energy and mass exchanges at ground • ---interactions among soil science, hydrological cycles • (ground and air), ecosystems, and atmosphere. • Canopy • Terrain • Heterogeneous surfaces • Clouds/fog • Urban environment, air pollution

  4. Surface heterogeneity • Leaf stomatal control • Soil properties • Induced circulations • Internal boundary layer Internal boundary layer fully adjusted

  5. Convective Internal Boundary Layers

  6. Schematic diagrams of potential temperature profiles after changes in surface temperature (heat flux). (a) development of an advective inversion after a hot-cold transition (b) growth of a CIBL after a cold- Hot transition (c) structure of a CIBL at longer fetch. Kaimal & Finnigan, 1994

  7. Effects of Heterogeneity on Flux Measurement in the Surface Layer Horst and Weil (1994, JTECH) show via modeling studies how far upstream surface fluxes originate that are measured via eddy correlation from a tower in the SL. This is known as the flux “footprint.” This is an important issue in flux measurement over heterogeneous terrain.

  8. Note strong effect of stability on required fetch for flux measurement

  9. Homogeneous

  10. Heterogeneous l/zi ~ 9

More Related