Retrieval of Airglow Emission Rates in Analytical Form for Limb‐viewing Satellite Observations at Low Latitudes

AbstractThis study investigates how subgrid cloud water inhomogeneity within a grid spacing of a general circulation model (GCM) links to the global climate through precipitation processes. The effect of the cloud inhomogeneity on autoconversion rate is incorporated into the GCM as an enhancement factor using a prognostic cloud water probability density function (PDF), which is assumed to be a truncated skewed-triangle distribution based on the total water PDF originally implemented. The PDF assumption and the factor are evaluated against those obtained by global satellite observations and simulated by a global cloud-system-resolving model (GCRM). Results show that the factor implemented exerts latitudinal variations, with higher values at low latitudes, qualitatively consistent with satellite observations and the GCRM. The GCM thus validated for the subgrid cloud inhomogeneity is then used to investigate how the characteristics of the enhancement factor affect global climate through sensitivity experiments with and without the factor incorporated. The latitudinal variation of the factor is found to have a systematic impact that reduces the cloud water and the solar reflection at low latitudes in the manner that helps mitigate the too-reflective cloud bias common among GCMs over the tropical oceans. Due to the limitation of the factor arising from the PDF assumption, however, no significant impact is found in the warm rain formation process. Finally, it is shown that the functional form for the PDF in a GCM is crucial to properly characterize the observed cloud water inhomogeneity and its relationship with precipitation.

Download Full-text

Seasonal MLT-region nightglow intensities, temperatures, and emission heights at a Southern Hemisphere midlatitude site

Annales Geophysicae ◽

10.5194/angeo-35-567-2017 ◽

2017 ◽

Vol 35 (3) ◽

pp. 567-582 ◽

Cited By ~ 6

Author(s):

Iain M. Reid ◽

Andrew J. Spargo ◽

Jonathan M. Woithe ◽

Andrew R. Klekociuk ◽

Joel P. Younger ◽

...

Keyword(s):

Southern Hemisphere ◽

Satellite Observations ◽

Constant Density ◽

Meteor Radar ◽

Airglow Emission ◽

Broadband Emission ◽

Mlt Region

Abstract. We consider 5 years of spectrometer measurements of OH(6–2) and O2(0–1) airglow emission intensities and temperatures made near Adelaide, Australia (35° S, 138° E), between September 2001 and August 2006 and compare them with measurements of the same parameters from at the same site using an airglow imager, with the intensities of the OH(8–3) and O(1S) emissions made with a filter photometer, and with 2 years of Aura MLS (Microwave Limb Sounder) v3.3 temperatures and 4.5 years of TIMED SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics Sounding of the Atmosphere using Broadband Emission Radiometry) v2.0 temperatures for the same site. We also consider whether we can recover the actual emission heights from the intercomparison of the ground-based and satellite observations. We find a significant improvement in the correlation between the spectrometer OH and SABER temperatures by interpolating the latter to constant density surfaces determined using a meteor radar.

Download Full-text

Coordinated Satellite Observations of the Very Low Frequency Transmission Through the IonosphericDLayer at Low Latitudes, Using Broadband Radio Emissions From Lightning

Journal of Geophysical Research Space Physics ◽

10.1002/2017ja024942 ◽

2018 ◽

Vol 123 (4) ◽

pp. 2926-2952 ◽

Cited By ~ 5

Author(s):

Abram R. Jacobson ◽

Robert H. Holzworth ◽

Robert Pfaff ◽

Roderick Heelis

Keyword(s):

Low Frequency ◽

Satellite Observations ◽

Radio Emissions ◽

Very Low Frequency ◽

Broadband Radio ◽

Low Latitudes

Download Full-text

Results of Latitude Observations with the Floating Zenith Telescope at Mizusawa: Comparisons between the Results Obtained from the Astronomical and Doppler Satellite Observations

International Astronomical Union Colloquium ◽

10.1017/s0252921100051241 ◽

1975 ◽

Vol 26 ◽

pp. 461-468

Author(s):

S. Takagi

Keyword(s):

Photographic Plate ◽

Satellite Observations ◽

Pole Motion

In this article, we intended to see whether we can obtain the same pole motion from two kinds of telescopes: the floating zenith telescope (PZT) and the ILS zenith telescope (VZT). The observations with the PZT have been pursued since 1967.0 with a star list whose star places are taken from the PK4 and its supplement. We revised the method of reduction of the observations with the PZT by adopting a variable scale value for the photographic plate (Takagi et al., 1974).

Download Full-text

On the influence of specimen thickness in TEM images of super-conducting vortices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166087 ◽

1996 ◽

Vol 54 ◽

pp. 724-725

Author(s):

J. Bonevich ◽

D. Capacci ◽

G. Pozzi ◽

K. Harada ◽

H. Kasai ◽

...

Keyword(s):

Flux Line ◽

Analytical Form ◽

Realistic Model ◽

Electron Holography ◽

Specimen Thickness ◽

Flux Tubes ◽

Analytical Expression ◽

Flux Lines ◽

Normal Core ◽

Two Parameters

The successful observation of superconducting flux lines (fluxons) in thin specimens both in conventional and high Tc superconductors by means of Lorentz and electron holography methods has presented several problems concerning the interpretation of the experimental results. The first approach has been to model the fluxon as a bundle of flux tubes perpendicular to the specimen surface (for which the electron optical phase shift has been found in analytical form) with a magnetic flux distribution given by the London model, which corresponds to a flux line having an infinitely small normal core. In addition to being described by an analytical expression, this model has the advantage that a single parameter, the London penetration depth, completely characterizes the superconducting fluxon. The obtained results have shown that the most relevant features of the experimental data are well interpreted by this model. However, Clem has proposed another more realistic model for the fluxon core that removes the unphysical limitation of the infinitely small normal core and has the advantage of being described by an analytical expression depending on two parameters (the coherence length and the London depth).

Download Full-text