Alison Ming
I am a post-doctoral research associate in the Department of Applied Mathematics and Theoretical physics at the University of Cambridge.
My research focuses on the large scale processes in the stratosphere. Some of my current interests include understanding the radiative and dynamical interactions in the Uppper Troposphere/Lower Stratosphere region and exploring the seasonal to decadal aspects of the circulation.

Contact details

Alison Ming
DAMTP
Wilberforce road
CB3 0WA
UK
2015 — Research assistant
DAMTP
University of Cambridge
2011 — 2015 PhD student
DAMTP
Corpus Christi College
University of Cambridge
2007 — 2011 MSci
Corpus Christi College
University of Cambridge

Tropopause Inversion Layer

A key feature of the extratropical upper troposphere and lower stratosphere is a region of stable air located just above the tropopause. This region is commonly referred to as the tropopause inversion layer (TIL) since it is directly related to an inversion in the vertical temperature gradient i.e the vertical temperature gradient changes from a roughly steady decrease in the troposphere to a strong increase just above the tropopause.
This layer of air is a few kilometers thick and is located about 1 km above the extratropical tropopause. The region around the TIL is characterized by a strong connectivity between radiative, dynamical, chemical and microphysical processes and as a result is highly sensitive to climate change. Processes that contribute to the formation of the TIL are still not well understood and is one of my current research interests.

Double peaks in upwelling

The tropical lower stratosphere is the main entry pathway for air into the stratosphere. An interesting feature structure of the upwelling in the tropical lower stratosphere around 70 hPa is the presence of two maxima centred around latitudes 20 N and 20 S. Correspondingly there are two peaks in the diabatic heating at the same location. What makes this feature interesting is that the latitudinal temperature gradient is of the wrong sign to explain the peaks in heating. This heating cannot be regarded as purely relaxational. In my current work, I consider that this heating can be regarded as imposed. The structure in ozone is a key contributor to the heating structure and in an idealised model calculation, we have shown that a heating with a structure similar to observations can give rise to two peaks in the upwelling. These results can be found here and here.

Annual cycle in lower stratospheric temperatures

Air entering the stratosphere reaches particularly cold temperatures at around 90 hPa over the tropics. A large portion of the water vapour is freeze dried out leading to a dry stratosphere compared to the troposphere. The annual cycle in temperatures at this cold point modulates how much water vapour is removed as the air rises through the lower stratosphere. This cycle is imprinted on the water vapour and gives rise to the so-called water vapour "tape recorder" signal. A key part of understanding the water vapour distribution of the stratosphere involves understanding the large annual cycle in temperatures in this region.
This annual cycle peaks higher up at 70 hPa and my work has shown that the radiative effects of ozone and water vapour are both important contributors to the cycle in temperatures. In particular, there are complex non local interactions between radiation and dynamics in this region. By using a set of carefully constructed model experiments, it is possible to separate and quantify these interactions.
  • Ming A, P Hitchcock, P Haynes, 2016: The response of the lower stratosphere to zonally symmetric thermal and mechanical forcing. Journal of the Atmospheric Sciences doi: 10.1175/JAS-D-15-0294.1
  • Ming A, P Hitchcock, P Haynes, 2016: The double peak in upwelling and heating in the tropical lower stratosphere. Journal of the Atmospheric Sciences doi: 10.1175/JAS-D-15-0293.1
  • Ming A, 2015: Meeting report: Stratosphere–troposphere coupling in the Earth system: Where next? Weather doi: 10.1002/wea.2517