# Presentation: 051916

## Tutorial on Atmospheric Chemistry:

**Charles Jackman**
- Atmospheric Chemistry and Dynamics Branch
- NASA Goddard Space Flight Center, Greenbelt, MD

**CDAW Meeting – Jan. 6-9, 2009**

**Overview of the Ozone Layer**and the** Atmospheric Influences ****of Solar Proton Events**

## Overview of the Ozone Layer

## General Facts on Ozone

**Ozone = ****O****3  ****(three oxygen atoms) and is VERY reactive**

**Ozone is located mainly in the stratosphere **
**    ****(~12 to 50 km high)**
** **

**Ozone amounts are small – ****only several molecules of ozone in a million air molecules at most**

**Ozone absorbs ultraviolet (UV) light ****(****protects life****)**** and turns the light into heat – ****leads to first three layers of the atmosphere****  **

## O3  +  h (mainly UV)           O  +  O2
                                         or
                                                 O*  +  O2

O* is usually quenched to O

and generally 
O + O2 + M(N2,O2)       O3 + M 

-                                          or
-                                                  O*  +  O2
- O* is usually quenched to O
- and generally** **
**O + O****2**** + M(**N2,O2**)   ********    O****3**** + M**** **

**Ozone Heating**

**Can proceed a couple hundred times**
**  ****before O or O* react with another constituent!**

- (some visible, IR)

## Atmospheric Structure

- 180

- 200

- 220

- 240

- 260

- 280

- 300

- Temperature (K)

- 0

- 20

- 40

- 60

- 80

- 100

- Altitude (km)

- Troposphere

- Stratosphere

- Mesosphere

- Thermosphere

- Altitude (miles)

- 10

- 0

- 20

- 30

- 40

- 50

- 60

## Ozone is produced by UV photolysis of oxygen  

O2  +  h (<242 nm)       O  +  O

followed by

O + O2 + M       O3 + M 

O + O2 + M       O3 + M 

- O2  +  h (<242 nm)       O  +  O
- followed by
**O + O****2**** + M   ********    O****3**** + M **
**O + O****2**** + M   ********    O****3**** + M**** **

**Ozone Production**

## Ozone Destruction

**Ozone Destruction**

**Five families (or groups) responsible****:**
**Oxygen**
**Hydrogen**
**Nitrogen**
**Bromine**
**Chlorine**

## Ozone Destruction (continued)

**Ozone Destruction**** **(continued)

**Long-lived “source” gases move**
**Hydrogen**
**Nitrogen**
**Bromine**
**Chlorine**

**to the stratosphere**

## Ozone Destruction (continued)

**Ozone Destruction**** **(continued)

**For example:** **chlorine ****is transported by a number of long-lived source gases**

**    ****One of these is:**
**    ****CF****2****Cl****2 ****(CFC-12)**
**- Used as a refrigerant**

**Source gases are broken apart **
**by UV light in the stratosphere**

## CLAES (Cryogenic Limb Array Etalon Spectrometer), a Lockheed Martin instrument, on the UARS (Upper Atmosphere Research Satellite)measured CF2Cl2 (CFC-12)

**CLAES (Cryogenic Limb Array Etalon Spectrometer), ****a Lockheed Martin instrument,**** on the UARS (Upper Atmosphere Research Satellite)****measured CF****2****Cl****2 ****(CFC-12)**

**Thanks to:  PI - Aidan Roche, **
**Co-I’s - Jack Kumer, John Mergenthaler, **
**Richard Nightingale, etc.**
**for first global CF****2****Cl****2**** measurements**

## UARS   CLAESmeasured CF2Cl2 (CFC-12) in 1992

**UARS   CLAES****measured CF****2****Cl****2 ****(CFC-12) in 1992**

**ppbv**

**CFC-12 carried into stratosphere in the tropics by slow rising circulation**

**CFC-12 photolyzed in stratosphere by solar UV, releasing Cl**

**Cl catalytically destroys O****3**

## Cl   Catalytically Destroys Ozone

- Chlorine family cycle:
- 		Cl  +  O3    ClO  +  O2
-    		ClO  +  O    Cl  + O2

**Can proceed several hundred to over a thousand times**
**  ****before Cl or ClO react with another constituent!**

## Catalytic Destruction of Ozone

- 				 CH4 - **Natural, Man-made**)

**Nitrogen: NO****x**  (from N2O – **Natural, Man-made**)

- Other families that destroy ozone:
-     **Bromine: BrO****x**  (from CH3Br – **Natural, Man-made**
- 				Halons – **Man-made**)

- Chlorine family: ClOx
-    Source from chlorofluorocarbons [CFCs] – **Man-made,**
-     CH3Cl - **Natural**

**Catalytic Destruction of Ozone**

## Chemically-active “radicals” destroy ozone:
   For example –
   a) HOx:   H, OH & HO2
   b) NOx:   NO & NO2
   c) BrOx:   Br & BrO
   d) ClOx:   Cl & ClO

-    For example –
-    a) HOx:   H, OH & HO2
-    b) NOx:   NO & NO2
-    c) BrOx:   Br & BrO
-    d) ClOx:   Cl & ClO

**Catalytic Destruction of Ozone**

## Two Other Catalytic Ways of Destroying Ozone

**Main Nitrogen (NO****x****) family cycle:**
**	****	****NO  +  O****3****  ********  NO****2****  +  O****2**
**   ****	****	****NO****2****  +  O  ********  NO  +  O****2**

**We will return to these catalytic ways of destroying **
**Ozone, when discussing solar proton influences.**

**Example of Hydrogen (HO****x****) family cycle:**
**	****	****OH  +  O****3****  ********  HO****2****  +  O****2**
**   ****	****	****HO****2****  +  O  ********  OH  +  O****2**

## Ozoneas a function of Altitude and Latitudefrom UARS  HALOE (HALogen Occultation Experiment)

**Ozone****as a function of Altitude and Latitude****from UARS  HALOE **(HALogen Occultation Experiment)

## Ozonefrom UARS HALOEJan/Feb 1992

**Ozone****from UARS HALOE**Jan/Feb 1992

-  -60      -40     -20      0      20      40      60
-                         Latitude

- 60
- 45
- 30
- 15
-  0

- Altitude (km)

**High **
**Ozone**

**Low Ozone**

## Ozonefrom UARS HALOEJan/Feb 1992

-  -60      -40     -20      0      20      40      60
-                         Latitude

- 60
- 45
- 30
- 15
-  0

- Altitude (km)

**Peak Ozone**
**Production**

**Ozone****from UARS HALOE**Jan/Feb 1992

## Has the Ozone Layer Changedin the Past?

**Has the Ozone Layer Changed****in the Past?**

## First look at Chlorine-Containing Source Gas Change

**First look at Chlorine-Containing Source Gas Change**

**Updated Figure made by Dr. James Elkins from **Trends of the Commonly Used Halons Below Published by Butler et al. [1998]**, **All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC).** **

**5 years**

**42 years**

**85 years**

**CFC-11       **

**CH****3****CCl****3**

**CCl****4**

**CFC-113**

**Global CF****2****Cl****2**
**(CFC-12)**

**Other Cl-gases (ppt)**

**        ****1982        1986        1990        1994        1998        2002        2006**
**                                                        ****Year**

**~5% increase**
**    ****per year**

**Abundance (pptv)**

## First look at Chlorine-Containing Source Gas Change

**First look at Chlorine-Containing Source Gas Change**

**Updated Figure made by Dr. James Elkins from **Trends of the Commonly Used Halons Below Published by Butler et al. [1998]**, **All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC).** **

**5 years**

**42 years**

**85 years**

**CFC-11       **

**CH****3****CCl****3**

**CCl****4**

**CFC-113**

**Global CF****2****Cl****2**
**(CFC-12)**

**Other Cl-gases (ppt)**

**        ****1982        1986        1990        1994        1998        2002        2006**
**                                                        ****Year**

**~5% increase**
**    ****per year**

**Abundance (pptv)**

## First look at Chlorine-Containing Source Gas Change

**First look at Chlorine-Containing Source Gas Change**

**Updated Figure made by Dr. James Elkins from **Trends of the Commonly Used Halons Below Published by Butler et al. [1998]**, **All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC).** **

**5 years**

**42 years**

**85 years**

**CFC-11       **

**CH****3****CCl****3**

**CCl****4**

**CFC-113**

**Global CF****2****Cl****2**
**(CFC-12)**

**Other Cl-gases (ppt)**

**        ****1982        1986        1990        1994        1998        2002        2006**
**                                                        ****Year**

**~5% increase**
**    ****per year**

**Abundance (pptv)**

**Global CFCl****3**
**(CFC-11)**

## Global Total Ozone Change 

**Globally averaged TOMS observations provide the basis for testing models **

**  ****Caused by Chlorine **
**and Bromine increases**

## Global Total Ozone Change 

**Globally averaged TOMS observations provide the basis for testing models **

## Global Annual Average Total Ozone Impact

- Very large Solar Proton Events:  up to ~0.2% decrease
-                                                       [last for 1-2 yrs]

**Activate Cl/Br**

**Increased Cl/Br**

**More O****2**** dissociation at solar max (increased UV)**

**Temperature and wind changes affect ozone**

**To be discussed...**

## Global Annual Average Total Ozone Impact

- Very large Solar Proton Events:  up to ~0.2% decrease
-                                                       [last for 1-2 yrs]

**Activate Cl/Br**

**Increased Cl/Br**

**More O****2**** dissociation at solar max (increased UV)**

**Temperature and wind changes affect ozone**

**To be discussed...**

**Man-made Chlorine and Bromine are Important in Controlling ****Global Ozone Amounts!**

## Protection of Stratospheric Ozone

**   ****Policy-makers from 100+ countries met:**
** **
** ****Montreal Protocol (1987);   ******** amended in       ****	****London (1990); Copenhagen (1992)**
**No new production of CFCs and halons after December 31, 1995 for ****developed**** countries**
**Limited production of CFCs & halons for ****developing**** countries ******** until technology for substitutes could be transferred**

## Chlorine-Containing Gases

**Chlorine-Containing Gases**

**Updated Figure made by Dr. James Elkins from **Trends of the Commonly Used Halons Below Published by Butler et al. [1998]**, **All CFC-113 from Steve Montzka (flasks by GC/MS), and recent updates of all other gases from Geoff Dutton (in situ GC).** **

**Lifetime**
**50 years**

**Lifetime**
**102 years**

**5 years**

**42 years**

**85 years**

**CFC-11**

**CH****3****CCl****3**

**CCl****4**

**CFC-113**

**CFC-12**

**Other Cl-gases (ppt)**

**         ****1982          1986           1990          1994          1998           2002          2006**
**                                                        ****Year**

## Atmospheric Lifetimes

-  _Source Gas_		       _Lifetime_
- Chlorofluorocarbons         40-100 years or more
-      (CFCs), etc.
**        **

-  **Will take decades for atmosphere **
** ****to cleanse itself!**

## Global Total Ozone Change 

**Globally averaged TOMS observations provide the basis for testing models **

## Atmospheric Influencesof Solar Proton Events

## Introduction to Solar Proton Effects

## Slide 33

## Atmospheric Structure

- 0

- 20

- 40

- 60

- 80

- 100

- Altitude (km)

- Troposphere

- Stratosphere

- Mesosphere

- Thermosphere

- Tropopause

- Stratopause

- Mesopause

**Atmospheric Structure**

**GOES provides Proton flux**
**for >1 MeV to >100 MeV**

**Focus on protons **
**      ****<300 MeV**

## Solar Protons (<300 MeV) Deposit their Energy in both Polar Caps (>60o geomagnetic latitude) 

**Polar View **
**  ****of Earth**

**About 14% of Earth,**
**this area can be changed**
**during the event.**

##   Most (70-80%) of the Energy Deposited 

**by Protons (<300 MeV) Creates Ion Pairs:**
**  **
****** ****free Electron       &       positive Ion**

## ‘Bastille Day solar storm’ of 2000  

**- Caused a Major Solar Proton Event (SPE)**
**during July 14-16, 2000**

## Extremely Large SPE – GOES 8 Proton Flux Data (July 14-16, 2000) 

**> 10 MeV**

**> 50 MeV**

**> 100 MeV**

**10****4**

**Particles cm****-2****s****-1****sr****-1**** **

**10****3**

**10****2**

**10****1**

**10****0**

**10****-1**

**10****-2**

**    ****July 14           July 15         July 16****       **

## Proton Fluxes usedin Energy Deposition Codeto Compute Ionization Rates  

## Ionization rates (# cm-3 s-1) for July 2000 SPE

**Ionization rates (# cm****-3 ****s****-1****) for July 2000 SPE**

- Pressure (hPa)

- Altitude (km)

**Protons of energy 1 to 300 MeV used in this computation**

## Solar Protons also Produce HOx and NOx  - Both of which can destroy Ozone

- HOx (H, OH, HO2) produced through water cluster ion formation & neutralization
- Primarily short-term effects (during and for a few hours after SPE)
- NOx (N, NO, NO2) produced by protons & associated secondary electrons dissociating N2
- Short- and long-term effects as NOx constituents can last for weeks

## Solar Protons also Produce HOx and NOx  - Both of which can destroy Ozone

- HOx (H, OH, HO2) produced through water cluster ion formation & neutralization
- Primarily short-term effects (during and for a few hours after SPE)
- NOx (N, NO, NO2) produced by protons & associated secondary electrons dissociating N2
- Short- and long-term effects as NOx constituents can last for weeks

## Solar Protons also Produce HOx and NOx  - Both of which can destroy Ozone

**Solar Protons also Produce ****HO****x**** and NO****x  ****-**** **_***Both of which can destroy Ozone***_

- HOx (H, OH, HO2) produced through water cluster ion formation & neutralization
- Primarily short-term effects (during and for a few hours after SPE)
**NO****x**** (N, NO, NO****2****)**** produced by protons & associated secondary electrons dissociating N****2**
**Short- and long-term effects as NO****x**** constituents can last for weeks**

## Polar Ozone change 
due to the July 2000 SPE

**due to the July 2000 SPE**
**  **
**  **

## Percentage Change in Ozone at 0.5 hPa (~55 km) 

**Percentage Change in Ozone at 0.5 hPa (~55 km) **
**from ****July 13, 2000 to July 14/15, 2000**
**– ****Northern Hemisphere**

- NOAA-14 SBUV/2

## Whole Atmosphere Community Climate Model (WACCM) – Dan Marsh, Rolando Garcia, & Francis Vitt (NCAR)

Domain  [90oS – 90oN,  0 - 140 km]  
Atmospheric physics & photochemistry 
Interactive dynamics

 Simulations: ‘With’ and ‘Without’ SPEs 
			over years 2000 – 2001

- Domain  [90oS – 90oN,  0 - 140 km]
- Atmospheric physics & photochemistry
- Interactive dynamics
-  Simulations: **‘With’** and **‘Without’** SPEs
- 			over years 2000 – 2001

**Model**

## Whole Atmosphere Community Climate Model (WACCM) – Dan Marsh, Rolando Garcia, & Francis Vitt (NCAR)

Domain  [90oS – 90oN,  0 - 140 km]  
Atmospheric physics & photochemistry 
Interactive dynamics

 Difference simulations ‘With’ and ‘Without’ SPEs 
			over years 2000 – 2001

- Domain  [90oS – 90oN,  0 - 140 km]
- Atmospheric physics & photochemistry
- Interactive dynamics
-  Difference simulations **‘With’** and **‘Without’** SPEs
- 			over years 2000 – 2001

**Model**

## Percentage Change in Ozone at 0.5 hPa (~55 km) 

**Percentage Change in Ozone at 0.5 hPa (~55 km) **
**from ****July 13, 2000 to July 14/15, 2000**
**– ****Northern Hemisphere**

- NOAA-14 SBUV/2

## Percentage Change in Ozone at 0.5 hPa (~55 km) 

**Percentage Change in Ozone at 0.5 hPa (~55 km) **
**from ****July 13, 2000 to July 14/15, 2000**
**– ****Northern Hemisphere**

- NOAA-14 SBUV/2

- WACCM

**Ozone depletion at 0.5 hPa mainly driven by HO****x**** catalytic cycles, e.g.:**
**	****	****	****OH  +  O****3****   ********   HO****2****  +  O****2**
**	****	****	****HO****2****  +  O   ********   OH  + O****2**

## How did NOx change because of the July 2000 SPE?

**  **
**  **

## Maximum NOx effect in Fall and Winter
July is mid-Winter

NOx loss is minimum

Downward transport at poles
Bring NOx down to conserved region

**July is mid-Winter**
**NO****x**** loss is minimum**
**	****	****          **
**Downward transport at poles**
**Bring NO****x**** down to conserved region**

**Focus on Southern Hemisphere**

## Maximum NOx effect in Fall and Winter
July is mid-Winter

NOx loss is minimum

Downward transport at poles
Bring NOx down to conserved region

**July is mid-Winter**
**NO****x**** loss is minimum**
**	****	****          **
**Downward transport at poles**
**Bring NO****x**** down to conserved region**

**Focus on Southern Hemisphere**

## Difference Perturbed simulation ‘With SPEs’      and        Base simulation ‘Without SPEs’ 
    to compute SPE-caused change

**    ****to compute SPE-caused change**

**WACCM Comparisons**

## Pressure (hPa)

**     ****WACCM - NO****x**** (NO+NO****2****) change (ppbv)**
** **

**60-90****o****S**

- July              August               September
-                    Year 2000

##  Is there any evidence that a SPE-caused NOx enhancement could last weeks after an event?

Yes, Randall et al. (2001) 

**Yes, Randall et al. (2001) **
** **

## NOx (NO+NO2) in SH Polar Vortex in Sep./Oct. 

**NO****x**** (NO+NO****2****) in SH Polar Vortex in Sep./Oct. **

**UARS HALOE**

**WACCM (wo SPEs)**

**2000**

**from Randall et al. (2001)**

******  ****~15 ppbv ******

**Likely caused by the **
**July 2000 SPE**

**0       5      10     15     20     25**
**              ****NO****x**** (ppbv)**

**Potential Temperature**

## 

		NOx enhances larger family NOy 
    (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, 
           ClONO2, BrONO2) 
Whose lifetime can be long (~months to years)

**	****	****NO****x**** enhances larger family NO****y**** **
**    ****(N, NO, NO****2****, NO****3****, N****2****O****5****, HNO****3****, HO****2****NO****2****, **
**           ****ClONO****2****, BrONO****2****)**
- Whose lifetime can be long (~months to years)

**Longer-term Model Simulation****of Solar Proton Events**

## Pressure (hPa)

**     ****WACCM - NO****y**** % change**

**60-90****o****S**

- J    A    S    O    N    D    J    F    M    A    M   J
-           Year 2000                 Year 2001

##  HNO3 precipitation leads to Nitrate in ice

 Since NOy ~10% enhanced in lower stratosphere, then HNO3 ~10% enhanced

 Expect up to 10% enhanced Nitrate in ice

 Some observations (McCracken et al. 2001) show >100% enhanced Nitrate in ice

** ****Since NO****y**** ~10% enhanced in lower stratosphere, then HNO****3**** ~10% enhanced**
** ****Expect up to 10% enhanced Nitrate in ice**
** ****Some observations (McCracken et al. 2001) show >100% enhanced Nitrate in ice**

**Quick Note on Solar Proton Event****Contribution to Nitrate ****Deposition in Ice**

## How about the Ozone impact?

**Reminder of NO****x**** catalytic cycle:**
**	****	****	****NO  +  O****3****   ********   NO****2****  +  O****2**
**	****	****	****NO****2****  +  O   ********   NO  + O****2**

**	****Net:****	****O****3****  +  O   ********   O****2****  + O****2**

##    WACCM  

- Pressure (hPa)

**   ****WACCM  **
**NO****y**** ****% change**

**60-90****o****S**

**J    A    S    O    N    D      J    F    M    A    M   J  **
**          ****Year 2000                 Year 2001**

##    WACCM  

- Pressure (hPa)

**   ****WACCM  **
**NO****y**** ****% change**

**60-90****o****S**

**J    A    S    O    N    D    J    F    M    A    M   J  **
**          ****Year 2000                 Year 2001**

**   ****WACCM  **
**Ozone ****% change**

**J    A    S    O    N    D      J    F    M    A    M   J****  **
**          ****Year 2000                 Year 2001**

- Pressure (hPa)

## Pressure (hPa)

**     ****WACCM - Ozone % change**

**60-90****o****S**

- J    A    S    O    N    D    J    F    M    A    M   J
-           Year 2000                 Year 2001

## Ozone Production by SPEs

**  ****NO****y**** from large SPEs (e.g. , 2000) transported to lower stratosphere and interfere with Cl****y**** and Br****y**** via**
**ClO + NO****2**** + M   ********   ClONO****2   ****+ M**
**BrO + NO****2**** + M   ********   BrONO****2  ****+ M**

**  ****Chlorine & Bromine losses for Ozone were reduced    ******** thus Ozone was increased**

## How about other episodesof very large Solar Proton Events?

## Largest 12 SPEs in Past 45 Years

**Largest 12 SPEs in Past 45 Years**

- 	 Date of			  Computed Rank
-          SPEs		              (NOx Production)
**October 1989**				**1**
**August 1972**				**2**
**July 2000**				**3**
**October 28-31, 2003****	****	****	****4**
**November 5-7, 2001**			**5**
**November 2000**			**6**
**September 2001**			**7**
**August 1989**				**8**
**November 23-25, 2001**		**9**
**September 1966****	****	****	****10**
**January 2005****	****	****	****            11**
**Sep. 29 – Oct. 3, 1989****	****	****12**

**Note that seven**
**of the largest SPEs**
**occurred in 2000-2005!**

## What is Solar Proton impact on Total Ozone?

- Pure chemistry impact
- Use simpler global model for simulations 1963-2010

## Predicted Impact of Solar Protons on Total Ozone (%) – chemistry effects only 

**Predicted Impact of Solar Protons ****on Total Ozone (%) – *****chemistry effects only***

**% Ozone**
**  ****change**

**-0.1**

**-0.2**

**-0.5**

**-1**

- from Jackman et al. (2008b)

## Polar Annual Average Total Ozone Impact

- Very large Solar Proton Events:   1 to 3% decrease
-                                                       [last 1-2 yrs]

**Larger variability at poles**

**Difficult to observe**

**Similar variability for global and at poles**

**Larger at poles**

**Very big at poles**

##   What does this mean regarding the Ground Level Enhancements (GLEs)?

****** ****Matthew DeLand has kindly provided Solar**** Backscatter UltraViolet (SBUV/2) Ozone data****    from satellites NOAA-11, -14, -16, -17, -18**

## NOAA-14 SBUV/2: 

**NOAA-14 SBUV/2: **
**>60****o**** geomag. lat.**
** **
**for July 12-19, 2000**
**period**

**  ****12        14        16        18       **
**           ****Days of July, 2000**

**4 hPa**

**2 hPa**

**1 hPa**

**0.5 hPa**

**10 hPa     **(+2 ppmv)

**Figure 3: Jackman et al. (2001)**

## NOAA-14 SBUV/2: 

**Figure 3: Jackman et al. (2001)**

**NOAA-14 SBUV/2: **
**>60****o**** geomag. lat. **
** **
**for July 12-19, 2000**
**period**

**  ****12        14        16        18       **
**           ****Days of July, 2000**

**4 hPa**

**2 hPa**

**1 hPa**

**0.5 hPa**

**Model:**
**         ****NO****x ****only**
**         ****HO****x**** & ****NO****x**** **

**10 hPa     **(+2 ppmv)

## NOAA-14 SBUV/2: 

**Figure 3: Jackman et al. (2001)**

**NOAA-14 SBUV/2: **
**>60****o**** geomag. lat. **

**  ****12        14        16        18       **
**           ****Days of July, 2000**

**4 hPa**

**2 hPa**

**1 hPa**

**0.5 hPa**

**Model:**
**         ****NO****x ****only**
**         ****HO****x**** & ****NO****x**** **

**10 hPa     **(+2 ppmv)

## Reminder about Ozone Decreases

**HO****x**** constituents are short-lived (~hours), **
**thus most Ozone loss at 0.5 and 1 hPa is short-lived.**

**NO****x**** constituents are longer-lived (~weeks), **
**thus some Ozone loss at 2 and 4 hPa is longer-lived.**

## Prediction of Ozone Change for GLE Time Periodsusing Ion Pair Production* 

**1) <100 cm****-3**** s****-1****  ~0% ozone loss **
-         [02.May.1998 & 06.May.1998]
**2) 100-200 cm****-3**** s****-1****  ~4-8% ozone loss at 0.5 & 1 hPa**[06.Nov.1997,24.Aug.1998,15.Apr.2001,18.Apr.2001, 26.Dec.2001, 24.Aug.2002, & 13.Dec.2006]
**3) >500 cm****-3**** s****-1****  >8% ozone loss at 0.5 & 1 hPa**** **[14.Jul.2000,04.Nov.2001,28.Oct.2003,29.Oct.2003, 02.Nov.2003, 17.Jan.2005, & 20.Jan.2005]

******Threshold about 100 cm**-3** s**-1** for any ozone impact**(McPeters and Jackman, 1985)*

## Daily Average Ionization Ratesaround 14.Jul.2000 Contour intervals 100, 200, 500, 1000, 2000, 5000, and 10000 cm-3 s-1 

## Daily Average Ionization Ratesaround 04.Nov.2001 Contour intervals 100, 200, 500, 1000, 2000, and 5000 cm-3 s-1 

## Daily Average Ionization Ratesaround 28.Oct.2003, 29.Oct.2003, and 02.Nov.2003 Contour intervals 100, 200, 500, 1000, 2000, and 5000 cm-3 s-1 

## Daily Average Ionization Ratesaround 17.Jan.2005 and 20.Jan.2005 Contour intervals 100, 200, 500, and 1000 cm-3 s-1 

## Ozone Effects during GLEs 

**If any ozone depletion at all, **
**    ****then largest at 0.5, 1, and 2 hPa**** **

**Near GLEs in Jul. 2000; Nov. 2001; Oct./Nov. 2003; Jan. 2005  ******** should be easy to observe**** **

**Papers in literature about ozone effects from solar protons in Oct./Nov. 2003;   ****Jul. 2000;****    ****Jan. 2005;****    ****Nov. 2001****  **
**    ****[Size of font indicates approximate number of papers for each GLE period] **

## Outstanding Issue 

*** ***
**Solar Proton Event (SPE) contribution to nitrate deposition in ice**** **

*** ***
-      *Some studies show a large enhancement in nitrate from very large SPEs   (>100%)    [e.g., McCracken et al. 2001],*
*    **while others (and models) show a small enhancement (~10%)     [e.g., Palmer et al. 2001]*

## Thank you for your attention!