Assessing The Impact of LULCC on The Greater Phoenix Area

Assessing The Impact of LULCC on The Greater Phoenix Area

Matei GeorgescuMatei GeorgescuCenter for Environmental Prediction – Rutgers UniversityCenter for Environmental Prediction – Rutgers University

The Fourth Symposium on Southwest HydrometeorologyThe Fourth Symposium on Southwest HydrometeorologyTucson, ArizonaTucson, Arizona

September 20-21, 2007September 20-21, 2007

Topic Outline

• Introduction/Scientific Question

• Method of Investigation/Numerical Modeling

• Impact of Hypothetical LULCC over Greater Phoenix area

• Assessment of 30 years of LULCC over Greater Phoenix area

• Concluding Remarks and Future Work

Georgescu ([email protected])Georgescu ([email protected])Assessing The Impact of LULCC on Assessing The Impact of LULCC on

The Greater Phoenix AreaThe Greater Phoenix Area

Growth of Recorded Subdivisions in Maricopa County (1900-2007)

Source: http://www.maricopa.gov/assessor/



http://www.maricopa.gov/assessor/

Urban Population Explosion

Maricopa & Pinal Counties

Total of Major National Urban Areas (2000 Population Over 1 Million)

Year Population Annual Growth Rate PopulationAnnual Growth Rate

1900 28,236 20,439,707

1910 43,533 4.4% 27,316,248 2.9%

1920 105,706 9.3% 34,429,902 2.3%

1930 173,051 5.1% 44,613,809 2.6%

1940 215,034 2.2% 48,677,906 0.9%

1950 374,961 5.7% 59,922,430 2.1%

1960 726,183 6.8% 76,934,142 2.5%

1970 1,035,438 3.6% 91,258,448 1.7%

1980 1,599,970 4.4% 99,239,037 0.8%

1990 2,238,480 3.4% 111,908,809 1.2%

2000 3,251,876 3.8% 127,353,534 1.3%

100 Year 4.9% 1.8%

50 Year 4.4% 1.5%

Source: http://gp2100.org/



http://gp2100.org/

C:\Documents and Settings\tucson.DDB6FR21\Desktop\ThuPM1\george -Tucson2007\Phoenix.mov

Scientific Question

• Can we quantify the impacts of LULCC on local and regional weather and climate?

• What can we say about specific land-atmosphere interactions and possible feedbacks controlling these impacts?

• With expansion expected to occur for at least the next 50 years what consequences may be expected?

• As sprawl continues in the Greater Phoenix area, can we use lessons learned from this case study to mitigate effects from other rapidly urbanizing cities in arid areas (e.g., Las Vegas, Riyadh)?



• 38 Vertical Levels with 12 levels in the first 1500 m.

• RAMS Convective Parameterization: Kain-Fritsch.

• Interactive Soil and Vegetation Model (LEAF II).

• Initial Surface Boundary Condition: NARR Reanalysis Soil Moisture/Temperature of corresponding year.

• Nudging at lateral boundaries with 6-hr NARR data.

RAMS [v 4.3] nested grid domain configuration



Dominant LULC representation for fine grid employing circa 2001 (a), circa 1992 (b), circa 1973 (c) landscape, and a hypothetical land cover scenario (i.e., pre-1900) with anthropogenic influence removed (d).

Fine grid LULC representation

(a)

(c)

(b)

(d)

urban

irr. agriculture

shrubland



Impact of Hypothetical LULCC over Greater Phoenix area

Sensitivity of Summer Climate to Land Cover Change over the Greater Phoenix, AZ, Region (2007), Submitted to GRL



Summary of experiments

Summary of all 12 experiments performed. For each experiment, the analysis time consists of the period lasting from July 1, 12Z through July 31, 12Z. ** denotes experiment used as Control simulation which was validated against observations.

LULC Year from which Initial and Boundary Conditions were used to force RAMS

WET Years DRY Years

NLCD92 1990** 1994

Pre-Settlement 1990 1994

NLCD92 1984 1989


NLCD92 1983 1979





Comparison to Observations

Observed three-hourly 1.5 meter air temperatures (black) and RAMS simulated 2-meter temperatures from the control run simulation (red) during the period July 1st -12Z to July 31st -12Z, 1990. Units are in [°C]. The time series represent temperatures averaged over five stations: (1) Sky Harbor International Airport, (2) Phoenix Encanto, (3) Phoenix Greenway, (4) Waddell, and (5) Maricopa Agricultural Station.


observations

simulation



Comparison to Observations

Mean monthly temperature comparison between RAMS-simulated control experiment and station-observations for July 1, 12Z - July 31, 12Z, 1990.

Station July 1 12Z – July 31, 12Z [1990] Mean Temperatures [°C]

Observed Simulated

Phoenix – Sky Harbor

34.37 30.88

Phoenix - Encanto

32.08 30.62

Phoenix - Greenway

31.98 28.65

Waddell 32.76 27.56

Maricopa Agricultural Station

30.13 31.91

Regional Average

32.27 29.92




RAMS simulated ensemble differences (NLCD92 - Pre-Settlement) in (a) first atmospheric level [24.1 m] air temperature [°C] and (b) dew point [°C], for the WET years; (c) first atmospheric level [24.1 m] air temperature [°C] and (d) dew point [°C], for the DRY years. Each calculation is for the analysis period: July 1, 12Z – July 31, 12Z.


(a) (b)

(c) (d)

Temperature Dew-point



RAMS simulated ensemble differences (NLCD92 - Pre-Settlement) in (a) total accumulated precipitation [mm] for all 3 WET years; (b) total accumulated precipitation [mm] for all 3 DRY years;


(a) (b)

Precipitation



RAMS simulated ensemble member differences (NLCD92 - Pre-Settlement) in total accumulated

precipitation [mm] for (a) 1994, (b) 1989, and (c) 1979.

(a) (b) (c)


Precipitation




(a) domain-averaged [lat: 33 to 34/lon: -112.2 to -111.0] vertical profile of equivalent potential temperature difference (NLCD92 - Pre-Settlement) for selected DRY year cases; (b) as (a), but averaged over each DRY year simulation for the analysis period: July 1, 12Z – July 31, 12Z.

(a) (b)

Equivalent Potential Temperature



RAMS simulated ensemble differences (NLCD01 minus NLCD73) in (a) first atmospheric level [24.1 m] air temperature [°C] and (b) dew point [°C], for all three WET years; (c) first atmospheric level [24.1 m] air temperature [°C] and (d) dew point [°C], for all three DRY years. Each calculation is for the analysis period: July 1, 12Z – July 31, 12Z.

Temperature Dew-point

(a)

(c)

(b)

(d)



RAMS simulated ensemble differences (NLCD01 minus NLCD73) in surface sensible heat flux (a) for all three WET years, and (b) all three DRY years. RAMS simulated ensemble differences (NLCD01 minus NLCD73) in surface latent heat flux (c) for all three WET years and (d) all three DRY years. Each calculation is for the analysis period: July 1, 12Z – July 31, 12Z. All units expressed in W m -2.

(a)

(c)

(b)

(d)

Sensible Heat Flux Latent Heat Flux



Concluding Remarks/Future Work

• Offsetting contributions of irrigated agriculture and urbanization (in a regionally-averaged sense) are specified.

• Greater-Phoenix region induced impact on precipitation is noted during particular atmospheric regime.

• Preliminary assessment of 30 years of LULCC over Greater Phoenix indicates warmer and drier climate.

• What does the future hold in terms of continued growth rate and continued landscape alteration?

Source: http://gp2100.org/



http://gp2100.org/