Identification

Title

Nonmigrating tidal impact on the CO2 15 μm infrared cooling of the lower thermosphere during solar minimum conditions

Abstract

Carbon dioxide (CO2) infrared emissions at 15m is the primary radiative cooling mechanism of the thermosphere in the altitude range of 100-135km. This paper explores the role of two important diurnal nonmigrating tides, the DE2 and DE3, in the modulation of CO2 15m emissions during the solar minimum year 2008 by (i) analyzing Sounding the Atmosphere using Broadband Emission Radiometry (SABER) CO2 cooling rate data and (ii) photochemical modeling using dynamical tides from the empirical Climatological Tidal Model of the Thermosphere model. Tidal diagnostics of SABER data shows that the CO2 cooling rate amplitudes for the DE2 and DE3 components are on the order of approximately 20-50% relative to the monthly means, and they maximize around the lower bound (100km) of the analyzed height interval. The photochemical modeling reproduces the observed results, albeit with systematic amplitude differences which is likely related to the uncertainty in the model input backgrounds, especially atomic oxygen. The main tidal coupling mechanism is found to be the temperature dependence of the collisional excitation of the CO22 vibrational state. However, neutral density becomes equally important above approximate to 110km, thereby explaining observed evanescent DE2 and DE3 phases which are not present in temperature tides. The contribution of vertical tidal advection is comparatively small. The relative importance of the coupling mechanisms is the same at all latitudes/seasons. These results indicate that upward propagating nonmigrating tides forced by latent heat release in the lower atmosphere impact the thermospheric energy budget by modulating the longitudinal/local time behavior of the CO2 infrared cooling.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7br8vnq

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2017-06-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact