Latitudinal Gradients in the Earth’s Energy Budget

Solar Flux Impinging on Top of Earth’s Atmosphere Solar Flux Earth Figure 3.1

Spherical Geometry Figure 3.2

Daily Average Insolation (Top of Atmosphere) Figure 3.3

Courtesy of NASA ERBE/ Hartmann Figure 3.4

Courtesy of NASA ERBE/Hartmann Annual Mean Figure 3.5

Courtesy of NASA ERBE/Hartmann Annual Mean Figure 3.6

Courtesy of NASA ERBE

Courtesy of NASA ERBE/Hartmann Annual Mean Figure 3.7

Annual Mean Annual Mean Net Radiation Figure 3.8

How to Calculate the Atmosphere-Ocean Heat Flux across a Latitude Band South Pole Integrate R TOA from the South Pole over the entire polar cap to calculate the northward heat flux across a latitude band.   /2 R TOA = Shortwave absorbed - Longwave out = Polar Cap Figure 3.9

Annual Mean Required Atmosphere-Ocean Heat Transport Figure PW=10 15 Watts

Problems with the Use of Radiosonde Data to Determine Transport Strongest poleward eddy-induced heat transport occurs where there are few radiosondes, in the oceanic storm tracks. Lau (1978) Figure 3.11

Simplified Atmosphere Governing Equations used in Data Assimilation Wind (F=ma) Temperature Water Vapor Mass Conservation Vertical Balance (F=ma) The circled quantities on the right represent the effects of clouds, radiation, evaporation, and friction on the atmosphere. These terms represent sub-gridscale processes and thus must be parameterized. from Trenberth (1992) Figure 3.12

Parameterization within Observational Analysis Models. Example: Cumulus Parameterization Cumulus parameterization schemes take grid-scale humidity and temperature data from a column of grid cells. The parameterization tries to simulate the population of clouds that might exist within the column of cells, and then determines how this population of clouds alters the grid- averaged temperature and humidity. Some newer schemes also account for the effect of cumulus clouds on the grid-scale winds. Radiation parameterizations then use these estimated cloud populations and their effects on cloud liquid water to determine cloud-radiation interactions. This is a very difficult problem 300 km Figure 3.13

Atmospheric Meridional Heat Transport (As a Function of Dataset) TOA Net Radiation Total and Atmospheric Transports Figure 3.14 Differences can be seen depending on what atmospheric dataset is used. Trenberth and Caron (2001)

Atmospheric Meridional Heat Transport as a Function of Month Figure 3.15 Atmospheric heat transport largest in winter hemisphere. From Trenberth and Caron 2001

Direct Ocean Measurements Ganachaud and Wunsch (2000) Temperature and salinity measurements across ocean transects can be used to measure ocean heat flux. Figure 3.16

Ocean Meridional Heat Transport Calculated Using Three Different Methods Figure 3.17 From Trenberth and Caron 2001 Methods a) and c) Atlantic Methods a) and b) Atlantic Methods a), b), and c) World Ocean

More Recent Partitions of Atmosphere –Ocean Heat Transport (suggest a larger atmosphere role) Trenberth and Caron (2001) Figure 3.18 ocean R TOA atm