1. Macquarie Island (54.6 S, E)

2. Meteorological Records dating back to 1948
Surface observations
Can be found at
Observations have been used for a variety of studies
Adams (2009) reported a 35% increase in precipitation from (predominantly in winter.)
Hande et al (GRL 2012) reported surface winds increasing a ~3 cm/s/year from

4. Light precipitation (P < 0
Light precipitation (P < mm/h) is common at Macquarie Island for observations, ERA-I and CloudSat.
Strong precip (P > 1 mm/h) commonly associated with frontal activity (although the definition of fronts is not that consistent.)
The standard CloudSat precip product often records ice or mixed phase, especially in winter (no quantitative precip available.)

5. Previous Field Observations
Russell et al. (1998) identifies a ‘buffer layer’ above the boundary layer during ACE-1.
Jensen et al. (2000) identifies an ‘intermediate layer’ above the boundary layer during SOCEX II.

6. Can we identify a ‘buffer layer’ in the soundings from Macquarie Island? What about the ECMWF operational analysis for the Year of Tropical Convection (YOTC)?
Soundings:
Low resolution
Data interpolated on to standard levels plus additional levels at inversions
High Resolution:
10 second vertical resolution
YOTC ECMWF operational analysis

7. Example of a decoupled boundary layer with shear over the secondary inversion (ie. a buffer layer). Hande et al. (JGR 2012)
MAC YOTC

8. Boundary Layer Height BL height: primary inv 0.01 K/m 84.4% of MAC
52.3% of YOTC
MAC median = 1278 m
MAC std = 624 m
YOTC median = 1050 m
YOTC std = 524 m

9. Height of Secondary Inversion
BL height: secondary (decoupled) inv: K/m
66.6% of MAC
22.7% of YOTC
MAC median = 680 m
YOTC median = 734 m

10. Soundings normalized to the primary inversion
MAC YOTC
Compared to the YOTC, the MAC boundary layer is, on average:
more stable
has weaker winds
less shear

11. Boundary layer classification:
Type 1: No significant inversion
Type 2: Single well mixed layer with
0.01 K/m
Type 3: A ‘decoupled’ BL with no shear across 2nd inversion ( K/m)
Type 4: A ‘decoupled’ BL with shear over secondary inversion (I.e. ‘Buffer Layer’)

12. How does resolution affect the statistics?
Type 1:
No Inversion
Type 2: Single Inversion
Type 3: Secondary Inversion
Type 4:
Buffer Layer
MAC
15.6
17.8
32.9
33.7
MACp ave
34.2
42.1
14.1
9.6
2008 – 2010
31.8
45.2
12.4
10.6
YOTC
47.6
29.6
20.6
2.2
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