Upload
hamza-knock
View
214
Download
0
Tags:
Embed Size (px)
Citation preview
Summer Dust Storms In PhoenixUpdated Station Climatology and Pattern Classifications
Craig ShoemakerNWS WFO TucsonJeffrey T. DavisNWS WFO Tucson
Objectives of Study Update and Validate Dust Storm Events at Sky Harbor International Airport.
Premise of Studies: Sky Harbor International Airport is centrally located enough with respect to the metropolitan area so that storms identified in the study can be assumed to be of major areal importance.
Objectives of Study Classify Large-Scale Patterns Associated with Dust Storms Events.
McCollum (1993) – “Large-scale Patterns Associated with Severe Summertime Thunderstorms over Central Arizona.” Identified 3 distinct patterns based on 31 cases from 1978-1990.
Brazel and Nickling (1986) – “The Relationship of Weather Types to Dust Storm Generation in Arizona (1965-1980).” Used large-scale patterns to identify 4 dust storm generation weather types:
Type 1 - Frontal Type 2 - Thunderstorm Type 3 - Tropical Disturbances Type 4 - Upper-level/cut off lows
Objectives of Study
Classify Mesoscale Patterns Associated with Dust Storms Events.
MacKeen (2001) – “Summertime Storm Initiation and Evolution in central Arizona.” Identified 3 storm repeat regimes.
Objectives of Study
Study the Annual Variability in Dust Storms for Possible Seasonal Predictors.
Phoenix Dust Storms 1948-2002Frequency by Year
0
2
4
6
8
10
12
14
1948
1952
1956
1960
1964
1968
1972
1976
1980
1984
1988
1992
1996
2000
Co
un
t
Duststorms
Study Methodology
Surface Data - Hourly Surface Observations for Phoenix Sky Harbor International Airport (PHX) for June through September 1948 to 2002. Climate Data from NCDC.
Upper-air Data – NCEP/NCAR reanalysis 12Z charts for identified Dust Storm days. Upper-air data from CDC.
Storm Data – Local Storm Data from 1959 to 2002. Storm Data from NCDC.
Data
Criteria Visibility and Present Weather - Visibility reduced to ½ a mile or less
with blowing dust reported (BLDU). Wind – Directional shift and/or increase in speed accompanying or
following the reduced visibility in blowing dust.
Objective 1: Updated Dust Storm Events
Average Statistics 1948-2002
Average Number of Dust Storms– 2.8 per year. Last 30 years- 1.6 per year. Average Arrival Time – 6:33 PM MST Average Wind Direction – Southeast (121
Degrees) Average Max Wind Speed – 43 MPH Average Visibility – ¼ of a mile
Total Number of Cases: 161
Summer Dust Storms Frequency by Month
Phoenix Dust Storms 1948-2002Frequency by Time of Month
05
101520253035404550
First ofJun
End ofJun
First ofJul
End ofJul
First ofAug
End ofAug
First ofSep
End ofSep
Co
un
t
All Storms
Peak in Late July and Early August
Summer Dust Storms Frequency by Time
Phoenix Dust Storms 1948-2002Frequency by Time
0
5
10
15
20
25
30
35
Co
un
t
All Storms
Peak between 5 and 8 PM MST
Summer Dust StormsFrequency by Wind Direction
Phoenix Dust Storms 1948-2002Frequency by Wind Direction
0
10
20
30
40
50
60
70
N NE E SE S SW W NW
Co
un
t
All Storms
Dominated by East to Southeast Approaches
Summer Dust Storms Frequency by Visibility
Phoenix Dust Storms 1948-2002Frequency by Visibility
0
20
40
60
80
100
120
1/4 mile or less Greater than 1/4 mile
Co
un
t
All Storms
33% that hit the airport do not meet NWS warning criteria
Summer Dust Storms Frequency by Wind Speed
Phoenix Dust Storms 1948-2002Frequency by Wind Speed
0
10
20
30
40
50
60
70
Less than 36mph
36-46 mph 47-57 mph 58 mph orGreater
Co
un
t
All Storms
Very few are accompanied by severe winds
Objective 2: Classified Large-Scale Patterns Severe Thunderstorm and Dust Storm Patterns
This study used 161 cases to identify 5 distinct Large-Scale Patterns Associated with Dust Storms. 8 cases could not be classified.
McCollum (1993) used 31 cases to identify 3 distinct Large-Scale Patterns Associated with Severe
Thunderstorms. 4 cases could not be classified.
McCollum (1993) Severe Thunderstorm Pattern I
Sources: http://www.wrh.noaa.gov/tucson/monsoon/severel.htmlhttp://www.cdc.noaa.gov/Composites/Day
• 9 cases out of 31 fit this pattern.• Broad High over Southern ½ US.• Deep Easterly Flow over TX, NM, AZ.
Phoenix Dust Storm Pattern I
Source: http://www.cdc.noaa.gov/Composites/Day/
• 40 cases out of 161 fit this pattern.• Broad High over US.• Deep Easterly Flow over TX, NM, AZ.
Dust Storm Pattern IPattern I
Frequency by Wind Direction
02468
1012141618
N NE E SE S SW W NW
Co
un
t
Pattern I
Phoenix Dust Storms 1948-2002Frequency by Arrival Time
0123456789
12PM
2PM
4PM
6PM
8PM
10PM
12AM
2AM
Co
un
t
Pattern I
Phoenix Dust Storms 1948-2002Frequency by Wind Speed
02468
1012141618
Less than 36mph
36-46 mph 47-57 mph 58 mph orGreater
Co
un
t
Pattern I
Phoenix Dust Storms 1948-2002Frequency by Visibility
0
5
10
15
20
25
30
1/4 mile or less Greater than 1/4 mile
Co
un
tPattern I
McCollum (1993) Severe Thunderstorm Pattern II
Sources: http://www.wrh.noaa.gov/tucson/monsoon/severel.htmlhttp://www.cdc.noaa.gov/Composites/Day/
• 9 cases out of 31 fit this pattern.• High Amplitude Ridge over Wrn US.• Northeast to East Flow over AZ.• Occasional weak cold front will move into AZ from the east with moisture from the high plains.
Phoenix Dust Storm Pattern II a
Source: http://www.cdc.noaa.gov/Composites/Day/
• 25 cases out of 161 fit this pattern.• High Amplitude Ridge over Wrn US. High cell centered near Srn NV or Srn UT.• North to East flow over AZ.
Dust Storm Pattern II a
Phoenix Dust Storms 1948-2002Frequency by Visibility
0
5
10
15
20
1/4 mile or less Greater than 1/4 mile
Co
un
t
Pattern IIA
Phoenix Dust Storms 1948-2002Frequency by Wind Speed
0
2
4
6
8
10
12
14
Less than 36mph
36-46 mph 47-57 mph 58 mph orGreater
Co
un
t
Pattern IIA
Phoenix Dust Storms 1948-2002Frequency by Arrival Time
00.5
11.5
22.5
33.5
44.5
12PM
2PM
4PM
6PM
8PM
10PM
12AM
2AM
Co
un
t
Pattern IIA
Phoenix Dust Storms 1948-2002Frequency by Wind Direction
0
1
2
3
4
5
6
7
8
N NE E SE S SW W NW
Co
un
t
Pattern IIA
Phoenix Dust Storm Pattern II b
Source: http://www.cdc.noaa.gov/Composites/Day/
• 38 cases out of 161 fit this pattern.• High Amplitude Ridge with High cell centered near 4 corners area. • Deep Easterly Flow over NM & AZ.
Dust Storm Pattern II bPhoenix Dust Storms 1948-2002
Frequency by Wind Direction
0
2
4
6
8
10
12
14
16
N NE E SE S SW W NW
Co
un
t
Pattern IIB
Phoenix Dust Storms 1948-2002Frequency by Wind Speed
02468
10121416
Less than 36mph
36-46 mph 47-57 mph 58 mph orGreater
Co
un
t
Pattern IIB
Phoenix Dust Storms 1948-2002Frequency by Time
0
2
4
6
8
10
12
12PM
2PM
4PM
6PM
8PM
10PM
12AM
2AM
Co
un
t
Pattern IIB
Phoenix Dust Storms 1948-2002Frequency of Visibility
0
5
10
15
20
25
30
1/4 mile or less Greater than 1/4 mile
Co
un
t
Pattern IIB
McCollum (1993) Severe Thunderstorm Pattern III
Sources: http://www.wrh.noaa.gov/tucson/monsoon/severel.htmlhttp://www.cdc.noaa.gov/Composites/Day/
• 9 cases out of 31 fit this pattern.• Broad High over Srn 1/3 of US. High cell positioned West of AZ and near FL. • Easterly flow over Nwrn Mexico.
Phoenix Dust Storm Pattern III
Source: http://www.cdc.noaa.gov/Composites/Day/
• 21 cases out of 161 fit this pattern.• Broad High over Southern US. Secondary High cell usually centered West of AZ. • Deep Easterly Flow over Nrn Mexico.
Dust Storm Pattern III
Phoenix Dust Storms 1948-2002Frequency by Visibility
0
2
4
6
8
10
12
14
Visibility 1/4 mile or less
Co
un
t
Pattern III
Phoenix Dust Storms 1948-2002Frequency by Time
0
1
2
3
4
5
6
7
12PM
2PM
4PM
6PM
8PM
10PM
12AM
2AM
Co
un
t
Pattern III
Phoenix Dust Storms 1948-2002Frequency by Wind Direction
0
1
2
3
4
5
6
7
8
N NE E SE S SW W NW
Co
un
t
Pattern III
Phoenix Dust Storms 1948-2002Frequency by Wind Speed
0
2
4
6
8
10
Less than 36mph
36-46 mph 47-57 mph 58 mph orGreater
Co
un
t
Pattern III
Phoenix Dust Storm Pattern IV
Source: http://www.cdc.noaa.gov/Composites/Day/
• 29 cases out of 161 fit this pattern.• Sharp Trough along the West coast.• Southwest to Southeast Flow over AZ.
Dust Storm Pattern IV
Phoenix Dust Storms 1948-2002Frequency by Visibility
0
5
10
15
20
25
Visibility 1/4 mile or less
Co
un
tPattern IV
Phoenix Dust Storms 1948-2002Frequency by Wind Direction
0
2
4
6
8
10
12
14
16
N NE E SE S SW W NW
Co
un
t
Pattern IV
Phoenix Dust Storms 1948-2002Frequency by Wind Speed
0
2
4
6
8
10
Less than 36mph
36-46 mph 47-57 mph 58 mph orGreater
Co
un
t
Pattern IV
Phoenix Dust Storms 1948-2002Frequency by Time
0
1
2
3
4
5
6
12PM
2PM
4PM
6PM
8PM
10PM
12AM
2AM
Co
un
t
Pattern IV
Objective 4: Study Annual Variability Future Work
Maricopa County Population Growth
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
1940 1950 1960 1970 1980 1990 2000
Po
pu
lati
on
Year
Maricopa County
Maricopa County population growth does not totally explain whysome years experience no dust storms at PHX.
Dust Storms by Decade
0
10
20
30
40
50
60
1940 1950 1960 1970 1980 1990 2000
Co
un
t
Dust Storms
JFM and AMJ La Nina (cold) and El Nina (warm) episodes from NCEP/CPC. Winter and Spring precipitation for AZ Climate Division 6. Average Palmer Drought Severity Index for AZ Climate Division 6. Satellite-derived vegetation Index.
Investigate the relationship between various parameters to dust storm frequency.
SUMMARY Updated Dust Storm Events (1948-2009) for PHX Sky
Harbor International Airport. Classified 5 distinct Large-Scale Pattern Associated with
Dust Storm Events.
Study 16 Dust Storm Events for possible classification of repeated storm regimes. Study various parameters for possible seasonal
predictors of Summer Dust Storm frequency.