Upload
amberlynn-miller
View
218
Download
0
Embed Size (px)
Citation preview
Tropospheric ozone variations revealed by high resolution lidar
M. J. Newchurch1, John Burris2, Shi Kuang1, Guanyu Huang1, Wesley Cantrell1, Lihua Wang1,
Patrick I. Buckley1, Xiong Liu3, Debra Hopson4
1 University of Alabama in Huntsville2 Goddard Space Flight Center, NASA
3Harvard Smithsonian Astrophysical Observatory4 Huntsville Department of Natural Resources and Environmental Management
The 3rd Asia Pacific Radiation SymposiumSeoul, South Korea25-28 August 2010
2Hey!!
Introduction
• High frequency of the ozone layer occurs in ozonesonde and Lidar profiles.
• The ozone layer has high potential implications for a variety of dynamic, chemical atmospheric processes and energy budgets (Newell et. al,. 2001).
• Due to their significance, dynamics and chemistry models should reproduce the ozone laminar structure (Stoller et al., 1999, Newell et al., 2001, Thouret et al., 2001).
• However, we have little understanding of the mechanisms of ozone layers. (Stoller et al., 1999, Newell et al., 2001, Thouret et al., 2001).
• In this study, we use two independent methods (Gradients and Wavelets) to study the mechanisms of ozone layer and its applications to models and satellite retrievals.
2
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
3
2007
3
4Hey!! 4
Using Difference Quotients to Find Extreme Points of Ozone Profiles
• Difference quotients are used to find extreme points of the mixing ratio.
• Local minima and maxima are filtered through to distinguish significant layers based on the threshold percent difference value.
• The threshold is defined as 15% difference between max and min.
• A 3-point boxcar average is applied to data before difference quotients are applied. Huntsville Ozonesonde Data
4
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
5
• The CWT coefficient is defined as:
• a is the spatial extent or dilation of the function.• b is the location at which the wavelet function
is centered—the translation of the function. • f(z) is the signal of interest, in this case, an
ozone profile. • and are the top and the bottom of the
profile. means wavelet function.
t
b
z
zf dza
bzzf
abaW )()(
1),(
tZ bZ
)(z
5
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
6
• Where there is a large gradient in the profile, the absolute value of CWT coefficient will be large.
• Therefore, we use CWT to detect the upper and lower boundaries of the ozone layer.
• In order to delete the “noisy” layer, two thresholds are set:
• The max of these two should > 10.0% and the min should > 3.0%. is the max ozone mixing ratio (MR) within the layer. and are the ozone MR at the upper and lower boundaries of the layer.
%100/)( maxmax b
%100/)( maxmax u
max
u b
6
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
7
Fairbanks
Pellston
Trinidad Head
Houston
Huntsville
Sable Island
Lidar and Ozonesonde Facilities used in this investigation
7
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
8
Seasonal Variations Occur in Altitudinal Distributions- Layer Height WRT to Tropopause Height
Gradient Wavelet
Spring
Summer High frequency of layers below tropopause
Low frequency of layers near tropopause
Trinidad Head
8
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
9
Layer Characteristics Vary Between Locations-Layer Height WRT to Tropopause Height (Wavelet)
Dec
reas
ing
Latit
ude
Fairbanks (1996-1997, 2001; 64.86, -147.85)
Pellston (2004; 45.59, -84.7)
Sable Island (1997; 43.96, -60.05) Houston (2000; 29.75, -95.43 )
9
The latitudinal trend of layer
frequency below the tropopause is captured by
both methods of analysis
The frequency of layers above the tropopause decreases as
latitude decreases; this is consistent for both methods
as well
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
Seasonal Peak Above Ground Level (Wavelets)
Huntsville
Spring Summer
Fall Winter
11
Layer B ThicknessMax: 4.8 km Min: 3.0 km
Mean Thickness: 0.3 km /10min
+0.9 km /10min
-0.3 km /10min
Layer A Max-MinMax: 50.1 ppbv Min: 36.6 ppbv
Mean max-min : 2.5 ppbv / 10min
+7.9 ppbv / 10min
-2.4 ppbv / 10min
A
B
•Temporal variability from other layer attributes can be similarly quantified.
•For example: O3 peak altitude, mixing ratio at peak.
Fine structure in the temporal variations of layer attributes can be quantified by Wavelet and Gradient methods from Lidar observations.
11
12Hey!!
1. Intense STE (~500ppbv at 7km) to reach top of the PBL (~2km) within 48 hours
12
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
13
10min, 500m resolution
O3 lidar retrieval
sonde
500ppbv
Cloud
CloudCloud
13
Cold front passage, clouds at 4-6km
sonde
14Hey!!
Apr. 23, 2010 Apr. 27, 2010 May 1, 2010
Dry stratospheric air
Tropopause
Co-located ozonesonde measurements
14
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
15http://nomads.ncdc.noaa.gov/
Huntsville
Dry air tongue
NAM RH pressure-time cross-section above Huntsville
http://nomads.ncdc.noaa.gov/
12Z 26 April~ 00Z 30 April, 2010
Dry air intrusion
lat:34.73, long: -86.65
16
17Hey!!
2. PBL ozone maximum due to post-front air stagnation. High surface ozone was also observed by the EPA station in Huntsville.
17
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
18Hey!!
Sonde, 1PM, May 8
May 5, 2010
May 7, 2010
May 6, 2010
May 3, 2010 May 4, 2010
EPA surface O3
Decoupling of surface and residual layer
Sonde
18
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
OzoneLidar (CNRS) during theESCOMPTE fieldCampaign (Marseilles area,summer 2001)
MOCAGE (Météo-France) equivalent to Lidar observations
Current models, even run at high resolution (10km and below) tend to underestimate above surface horizontal and vertical gradients as well as variability. This is a fundamental concern in the context of a changing climate : to what extent can we assess future evolutions (Air Quality, regional-scale radiative forcings,…)?
[email protected] on behalf of the MAGEAQ consortium
20Hey!!
3. Correlation between ozone and aerosol
20
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
21Hey!!
Positively correlated due to transport (from the same source)
Aerosol ext.coeff. at 291nm from O3 DIAL
Co-located ceilometer backscatter
Low-level jet
Co-located wind profiler
Positively correlated due to transport
Oct. 4, 2008
21
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
22Hey!!
Ozone mixing ratio, August 4, 2010
Aerosol ext.n coeff. At 291nm from O3 DIALDiurnal variation
Different variation structures for ozone and aerosol suggest local photochemistry dominates the ozone production
22
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
23Hey!! 23
4. Potential for using lidar measurements to address ozone variability captured by satellite
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
24Hey!!
Lidar observation, Aug. 4, 2010
Lidar convolved with OMI kernel
24
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010
Convolution of lidar ozone measurements between the surface and 10 km altitude at Huntsville, AL during August 4, 2010 with OMI ozone averaging kernel and a priori indicates that OMI is unable to capture the highly variable ozone structure in PBL, but captures a significant portion of the mid-tropospheric layer
25Hey!!
1. High spatio-temporal ozone variations are associated with different dynamic and photochemical processes from PBL to upper troposphere.
2. The ozone variations and structures sometimes are closely correlated with aerosol and sometimes not.
3. Nocturnal residual ozone layers often exist decoupled from the surface.
4. The lidar observations will be very helpful for addressing the ozone variability captured by geostationary satellites and forecast with regional air-quality forecasts.
Conclusions
25
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea25-28 August 2010