Verification for Different Contrail Parameterizations Based on Integrated Satellite Observation and ECMWF Reanalysis Data

Jinglin Zhang,Guoyu Zhang,Jian Shang

doi:10.1155/2017/8707234

Jinglin Zhang, Guoyu Zhang + Show 1 more

Open Access

https://doi.org/10.1155/2017/8707234

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Abstract

Aviation induced cloud termed contrail plays a more and more important role in the climate change, which makes a significant contribution to anthropogenic climate forcing through impacting the coverage of cirrus in the intersection of troposphere and stratosphere. In this paper, we propose one novel automatic contrail detecting method based on Himawari-8 stationary satellite imagery and two kinds of potential contrail coverage (PCC1 and PCC2) from contrail parameterization in ECHAM4 and HadGEM2. In addition, we propose one new climatological index called contrail occurrence and persistence (COP). According to the algorithm identification (AI) and artificial visual inspection (AVI), COP measured from Himawari-8 stationary satellite imagery is related to upper tropospheric relative humidity over ice (RHI) computed with the ECMWF reanalysis data by simple linear regression. Similarly, we compared the linear correlation between COP and PCCs fractions and found that PCC1 has better correspondence with COP than PCC2.

Highlights

The cloud is an important regulator of the energy budget of the earth system and the most significant uncertainty factor in climate change [1,2,3,4]
Detection efficiency suffers from underestimation of contrail width and contrail cirrus overlap, while the algorithm cannot detect weak contrail structures that can still be seen by the human eye
Contrails are important for understanding how the humans contribute to climate change by one artificial element into the atmosphere

Summary

Introduction

The cloud is an important regulator of the energy budget of the earth system and the most significant uncertainty factor in climate change [1,2,3,4]. Contrail is a special kind of cloud, caused by the aircraft engine emissions from the exhaust gas mixed with the surrounding air and the condensation of water vapor. The ambient relative humidity is close to saturation, and the atmospheric state is relatively stable to produce contrail. The formation of cirrus requires temperature below −40∘C and relative humidity of 145%–165% or more in the stable atmospheric state [5], while the contrail can persist in weakly saturated condition (relative humidity 100%–110%). Contrails are divided into three types: young, mature, and old in terms of contrail width and shape. A young contrail was defined as a linear shape with approximately a width less than 3 km and a maximum distance less than 200 km. The mature contrail maintains a linear shape with an approximate width less than 7 km. It can be observed that a mature contrail has larger brightness temperature difference (BTD) values than old contrails

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