Global-scale seasonally resolved black carbon vertical profiles over the Pacific.

J P Schwarz,F L Moore,Eric A Ray,B H Samset,R S Gao,M Schulz,A E Perring,J R Spackman,P Stier,D W Fahey

doi:10.1002/2013gl057775

Abstract

[1] Black carbon (BC) aerosol loadings were measured during the High-performance Instrumented Airborne Platform for Environmental Research Pole-to-Pole Observations (HIPPO) campaign above the remote Pacific from 85°N to 67°S. Over 700 vertical profiles extending from near the surface to max ∼14 km altitude were obtained with a single-particle soot photometer between early 2009 and mid-2011. The data provides a climatology of BC in the remote regions that reveals gradients of BC concentration reflecting global-scale transport and removal of pollution. BC is identified as a sensitive tracer of extratropical mixing into the lower tropical tropopause layer and trends toward surprisingly uniform loadings in the lower stratosphere of ∼1 ng/kg. The climatology is compared to predictions from the AeroCom global model intercomparison initiative. The AeroCom model suite overestimates loads in the upper troposphere/lower stratosphere (∼10×) more severely than at lower altitudes (∼3×), with bias roughly independent of season or geographic location; these results indicate that it overestimates BC lifetime.

Highlights

[2] The remote regions of the atmosphere at high altitude, and far from population centers, act as a sink for many
[3] Here we present a data set of airborne in situ measurements of Black carbon (BC) aerosol mass mixing ratios (MMRs) obtained via extensive vertical profiling of the remote atmosphere over global scales, with comparison to models
The measurements were collected as part of the High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) research aircraft campaign [Wofsy et al, 2011, 2012] with a single-particle soot photometer (SP2, Droplet Measurement Technology, Inc., Boulder, CO) during five 3 week measurements series mainly over the Pacific (Figure 1)

Summary

Introduction

[2] The remote regions of the atmosphere at high altitude, and far from population centers, act as a sink for many. [3] Here we present a data set of airborne in situ measurements of BC aerosol mass mixing ratios (MMRs) obtained via extensive vertical profiling of the remote atmosphere over global scales, with comparison to models.

Results

Conclusion