Mary Lear Global Hydrology and Resampling Flow Direction

Mary Lear Global Hydrology and Resampling Flow Direction Data April 22, 1999

Outline • Introduction – Global Hydrology and Climate System Model • Resampling Programs – Methodology – Interesting Concepts – River Networks

Global Hydrology • Tele-Connections • Interdisciplinary Studies

Climate System Model National Center for Atmospheric Research (NCAR) Boulder, Colorado • Predict greenhouse gas effects • Predict El Nino - La Nina • Precipitation-Evaporation • Deforestation changes • Ocean heating/cooling system • Historical Analysis

Model Output • Model output from 6 year run with 1% of land surface accounted for as surface water

Ocean Model • Compliments of LANL Parallel Ocean Program

Global River Network • Create manageable river network using fine resolution data • View of the world – Grid cells – Watersheds

Resampling Programs • Fine Resolution Flow Direction Data - 1 km • Coarse Resolution Output - 2. 814°

Resampling Methods • Two Methods – Inverse Maximum – Maximum Flow Accumulation • Written in Arc Macro Language (AML)

Inverse Method • Inputs – Flow Direction Grid – Scale Factor – Stream Delineation Threshold • Concept 1 MAXFAC ELEVATION

Inverse Method Output Fine Resolution River Network Inverse Output, ~200 scale factor

Maximum Method • Input – Flow Direction Grid – Projected Coarse Resolution Mesh – Checking Distance • Concept 1 2 FAC 1 FAC 2 10 12 FAC 10 Downstream FAC 12

Maximum Output • Export the PAT to Excel, Word • Generate Line Coverage

Future Work • Examine Inverse Method Completely • Add perks to Maximum Method – Code for Continental Margin – Flowlength Column • Write Comparison

Appreciations