Nitrogen Deposition at Rocky Mountain National Park: the RoMANS Study

Transcription

1 Nitrogen Deposition at Rocky Mountain National Park: the RoMANS Study Mike Barna Bill Malm Bret Schichtel Kristi Gebhart Air Resources Division National Park Service National Park Service U.S. Department of the Interior Ozone and NOx in the West Meeting November 11, 2009 Santa Fe, NM

2 RoMANS Nitrogen deposition at Rocky Mountain NP has exceeded a critical load of 1.5 kg/ha/yr RoMANS: Rocky Mountain Atmospheric Nitrogen and Sulfur Study Field measurement campaigns conducted in spring and summer of 2006 Which source regions / source types are contributing to N deposition at RMNP?

3 RoMANS participants FEDERAL GOVERNMENT AGENCIES NPS NOAA USGS USFS EPA STATE OF COLORADO Colorado State University Colorado Department of Public Health and Environment CONTRACTORS Air Resource Specialists University of California Desert Research Institute Research Triangle Institute

4 RoMANS objectives Characterize the atmospheric concentrations of sulfur and nitrogen species in gaseous, particulate and aqueous phases (precipitation and clouds) along the east and west sides of the Continental Divide (Organic Nitrogen?) GAS: NH 3, R-NH 2, NO X (NO+NO 2 ), NO Y (HNO 3, PAN, etc) PARTICLE: NH 4, NO 3, ORGANICS (reduced and oxidized)? WET (rain, snow, and clouds): NH 4, NO 3, ORGANICS (reduced and oxidized)? Identify the relative contributions to atmospheric sulfur and nitrogen species in RMNP from within and outside of the state of Colorado. Identify the relative contributions to atmospheric sulfur and nitrogen species in RMNP from emission sources along the Colorado Front Range versus other areas within Colorado. Identify the relative contributions to atmospheric sulfur and nitrogen species from mobile sources, agricultural activities, large and small point sources within the state of Colorado.

5 Concerns about N deposition Low capacity to sequester atmospheric N deposition N enrichment and shifts in diatom communities in alpine lakes N enrichment in organic soil layer and Engelmann spruce needles on eastern slope See Fenn et al. (2003) for review of N deposition ecological effects

6 Increasing wet N deposition Wet nitrate concentration deposition trends Wet ammonium concentration deposition trends

7 Sources of reduced/oxidized N Naturally Occurring Compound Anthropogenic NO 2 NO 3 Fossil-Fuel Combustion (power plants- mobile sources-oil and gas) Fertilizer, Prescribed fire Soil Release Lightning Wild fire NH 3 NH 4 Feedlots Fertilizer Mobile & Area Sources Wild animals Ecosystem respiration Organic N Feedlots-Fossil Fuel Combustion Vegetation

8 NH3 and NOx emissions What happens to emitted NOx & NH3? NH 3 : rapid deposition, NH 3 NH 4 +, no gasphase oxidation NO x : complicated photochemistry, HNO 3 NO 3 -, some species rapidly deposit (HNO 3, NO. ) NH3 NOx

9 2006 v NOx emissions in UBAQS

10 RoMANS field sites Grant, NE Dinosaur Timber Creek Loch Vale Beaver Meadows Brush Gore Pass Core Site Lyons Springfield

11 Core site at RMNP

12 RoMANS period typical? Concentration (mg/l Concentration (mg/ Spring (Mar 25 - Apr 30) Loch Vale N_NH4 N_NO3 Total N S_SO4 Climatology ( ) ROMANS (2006) Spring (Mar 25 - Apr 30) Beaver Meadows N_ NH4 N_ NO3 Total N S_ SO4 Climatology ( ) ROMANS (2006) Concentration (mg/l) Concentration (mg/l Summer (Jul 6 - Aug 11) N_NH4 N_NO3 Total N S_SO4 Climatology ( ) ROMANS (2006) Summer (Jul 6 - Aug 11) N_ NH4 N_NO3 Total N S_ SO4 Climatology ( ) ROMANS (2006)

13 RoMANS trajectories Rocky Mountain National Park Concentration Weighte Deposition Weighted Residence Time Heights = m, input = Hy47 EDASGDAS, Traj Len = 5 days, 1 Percent of Endpoints All days from January 1, 2000 December 31, 2007 < to to to to to to to to > All days from During RoMANS study period Mar 27, Aug 11, 2006 Weighted by N.TotDep.BM.kghay Includes Months: 3,4,7,8

14 Wind direction and concentration N neq/m precipitation W S E Wind Direction (degrees) 0 0 4/20 4/21 4/22 4/23 4/24 4/25 4/26 4/27 Date N SO 4 2- NO 3 - NH 4 + Wind Direction

15 Apportionment strategy Concentration gradients Which way is the wind coming from? Simple back trajectories Residence time analysis Trajectory receptor models Receptor models Chemical transport models Hybrid Models

16 NH 3 NO x

17 Wet Deposition (Spring) g/m 2 ) Wet Deposition N or S ( SO 4 NO 3 NH 4 DON mmprecip /26 3/29 4/15 4/17 4/18 4/23 4/24 4/ Precipitation (mm) Spring Average Wet NO3 Fractional Deposition Spring Average Wet NH4 Fractional Contribution Other 17% Denver 12% Other 39% East WY 7% Denver 52% Calif 1% Estes 1% East WY 6% NW CO 2% Northeastern CO 1% Northeastern CO 62%

18 Wet Deposition (Summer) Wet Deposition N or S ( g/m 2 ) SO 4 NO 3 NH 4 DON mmprecip /06 7/07 7/08 7/09 7/11 7/15 7/17 7/19 7/20 7/23 7/24 7/25 7/26 7/30 7/31 8/03 8/05 8/07 8/10 8/ Precipitation (mm) Summer Average NO3 Wet Dep Summer Average NH4 Wet Dep East WY 3% SW WY 2% Four Corners 8% NGS 2% Other 21% S Nevada 15% Denver 10% Calif 17% Western CO 3% Northeastern CO 3% Local 8% NW CO 5% Estes 3% East WY 2% SW WY 1% Calif 7% Other 24% Denver 2% Local 32% Western CO 24% Northeastern CO 7% Estes 1%

19 Wet + Dry Deposition for Spring and Summer (in state vs out of state)

20 Missing nitrogen measured species: missing N species: 20

21 N dry deposition of Rocky Mountain NP N dry deposition at RMNP based on CASTNet Only three N species are typically measured for dry deposition: NH 4 +, NO 3 - and HNO 3 What happens when we consider the dry deposition of total N at RMNP? Oxidized N (the NO y budget): NO x, HNO 3, NO 3 -, PAN + other organic nitrates, HONO, nitrate radical + N 2 O 5 Reduced N: NH 3, NH 4 + Simulate this missing N with CAMx

22 Modeled dry deposition at RMNP N-PAN 3% N-NxOy 10% N-Org N 2% N-NOx 4% N-PNH4 0% N-PNO3 0% N-HNO3 53% N-NH3 28% N-HONO 0%

23 Yearly CAMx and CASTNet estimates of dry deposited N at RMNP for 2002 N Dry Deposition [kg/ha/yr] N-PNO3 N-PNH4 N-NOx N-PAN N-NxOy N-Org N N-NH3 N-HONO 0.0 [HNO3,NO3,NH4] [HNO3,NO3,NH4] [Total N] CASTNet CAMX CAMX N-HNO3

24 New NHx measurements A new module to the IMPROVE sampler Measures both NH3 and NH4+ Proposed sites (likely to change): Chiricahua AZ Bandelier NM Mesa Verde CO Rocky Mtn CO Brooklyn Lake WY Yellostone WY Glacier MT Teddy Rosevelt ND Wind Cave SD Craters of the Moon ID

25 What we found A substantial portion of deposited Nitrogen originates from within the state of Colorado (about a 55:45 split) Of the reduced nitrogen about 70% comes from Colorado sources Of the Oxidized nitrogen the split is closer to 40% from Colorado sources During the Spring upslope conditions cause most of the N deposition. Associated with large single deposition episodes Reduced nitrogen is primarily from northeastern Colorado Oxidized nitrogen is primarily form Denver and its associated sources

26 What we found (cont d) During the summer deposition episodes are smaller but more frequent so that total deposition is greater than during the Spring. Sources of reduced nitrogen are about equally split between northeastern and western Colorado. Local emissions may also contribute significantly. Sources of oxidized nitrogen come from oil and gas and power plants in the 4-corners region and general transport form the southwest In general about ½ of total nitrogen deposition comes from the east and about ½ from the west More diverse sources contribute during the summer than spring.

27 The end

28 Process analysis in CAMx Order Process Information Units 1 Initial concentration µmole/m3 2 Gas phase chemistry µmole/m3 3 Area emissions µmole/m3 4 Point source emission µmole/m3 5 Plume-in-rid change µmole/m3 6 West boundary advection µmole/m3 7 East boundary advection µmole/m3 8 South boundary advection µmole/m3 9 North boundary advection µmole/m3 10 Bottom boundary advection µmole/m3 11 Top boundary advection µmole/m3 12 Dilution in the vertical µmole/m3 13 West boundary diffusion µmole/m3 14 East boundary diffusion µmole/m3 15 South boundary diffusion µmole/m3 16 North boundary diffusion µmole/m3 17 Bottom boundary diffusion µmole/m3 18 Top boundary diffusion µmole/m3 19 Dry deposition µmole/m3 20 Wet deposition µmole/m3 21 Heterogeneous chemistry µmole/m3 22 Final concentration µmole/m3 23 Units conversion ppm/(µmole/m3) 24 Average cell volume m 3

29 Process analysis: ammonia

30 Local dry deposition of ammonia