mesoscale observing challenges: one perspective with emphasis on the urban zone presentation to the:...

Mesoscale Observing Challenges: One Perspective with Emphasis on the Urban Zone

presentation to the:

NSF Observing Facilities Users Workshop

24-26 September 2007

NCAR

Boulder, CO

presentation to the:

NSF Observing Facilities Users Workshop

24-26 September 2007

NCAR

Boulder, CO

Walt Dabberdt

Director, Strategic Research

Vaisala - Boulder, Colorado

©Vaisala | date | Ref. code |

Presentation Outline

• Urban Demographics & Challenges

• Importance of the PBL

• Measurement Systems

• Mesoscale Networks and Testbeds


Ten(10) Largest Cities in 1000A.D. (M-Inhabitants)

Cordova Spain 0.450

Kaifeng China 0.400

Constantinople Turkey 0.300

Angkor Cambodia 0.200

Kyoto Japan 0.175

Cairo Egypt 0.135

Baghdad Iraq 0.125 (1.25???)

Nishapur Iran 0.125

Al-Hasa Saudi Arabia 0.110

Patan India 0.100

Source: Tertius Chandler: “4,000 Years of Urban Growth” (1987)


1950

2000

2015


Growth of Mega-Cities

City-2015 PopulationTokyoMumbaiLagosDhakaSao PauloKarachiMexico CityShanghaiNew YorkJakartaKolkataDelhiMetro ManilaLos AngelesBuenos AiresCairoIstanbulBeijingRio de JaneiroOsakaTianjinHyderabadBangkok

26.426.123.221.120.419.219.219.117.417.317.316.814.814.114.113.812.512.311.911.010.710.510.1

379.3 (23)Source: UN Population Division, March 2000

most mega-cities are in the less

developed regions (16)

blue = coastal city

green = inland city


The March of Urbanization in the World (% global population)

World MDR LDR

1950 29.8 54.9 17.8

1975 37.9 70.0 26.8

2000 47.2 75.4 40.4

2030 60.2 82.6 56.4

MDR = more developed regions

LDR = less developed regions source: UNPD, 2001

Today, 1.3 million people are moving to the cities every week!


Growth by City Size

Contrary to popular belief, the

bulk of urban population growth is likely to occur in smaller cities and towns of less than

500,000.


Some Relevant City Factoids (source: Arnulf Gruber, 2004)

• ~50% world population (~2007)

• > 80(?)% world GDP (few data)

• > 80(?)% world electricity

[wfd: ~ CO2 eq. emissions?; no good data]

• ~ 95% world internet sites and internet traffic (good data)

• 78% mega-cities are coastal [wfd]

• 70% mega-cities are in less-developed regions [wfd]


Warm Season Events • Tornadoes• Mesoscale boundaries• Mesoscale systems• Convection (localized)• Hurricanes/Tropical storms• Flash floods and main-stem

flooding• Fire weather events• Air quality episodes (O3)• Heat waves• Toxic plumes

Winter Season Events• Fronts/short-waves• Liquid/freezing/frozen boundaries• Ice storms• Orographic (e.g., lake effect

storms)• Blizzards/Wind chill• Coastal Gales• Air quality episodes (PM)• Cold air outbreaks• Toxic plumes

Examples of Mesoscale Events That Impact Human Well-Being and/or Have Major Economic Impacts


Tornado – Ft. Worth, TX

Source: North Central Texas Council of Governmentssimulation

March 28, 2000

Path Length: Approximately 3 miles Path Width: 1/4 mileF-Scale: F1 (73-112mph) to F2 (113-157mph)


MODIS Imagery: France Heat Wave -- August 13-28, 2003

Source: Zaitchik et al., 2006

Vegetation index anomaly Surface temperature anomaly

Solid lines demarcate conventional climate zones.


Three Recent Heat Waves

Event Year Location Fatalities

Heat wave 1987 Athens ~900 deaths

Heat wave 1995 Chicago ~700 deaths

Heat wave 2003 France ~15,000 deaths

Source: Earth Science and Applications from Space: National Imperatives for the

Next Decade and Beyond (2007)


Hurricane Katrina (2005) Tracks: Forecasts and Actual

Courtesy of James

Franklin, NHC


Mega-City Smog -- Beijing


Bi-directional physical problem with feedbacks:

•Weather and Climate Impacts on the City •Quality of life •Economy•Human health and mortality

•Urban effects on the atmosphereDirect: Indirect: sensible heat urban heat island runoff and latent heat human heat stress thermal conductivity and heat capacity PBL & ML structure aerodynamic roughness cloud cover & precip. zero-plane displacement insolation and radiation gaseous and particulate loading balance sun shading local circulations

City-Atmosphere Interactions


Why the Planetary Boundary Layer?

PBL contains the

Depth of cold air in winter to tops of stratocumulus

Low-level jet

for weather

Courtesy of Fed Carr, NAOS

Layer of air containing the roots of

summertime convection

Fog and low clouds under nocturnal

inversion

Convective events in well mixed layer

during daytime heating


The Need for Mesoscale Observations -- as Reported by the North American Observing System (NAOS) Study*

• Need to measure mesoscale phenomena at resolution that is high enough to accurately represent these mesoscale features in the initial conditions of a mesoscale model

• If using 6-8 grid points per wavelength criterion, then the needed resolution can be estimated as follows:

– 20-30 km resolution for jet streams, IPV details, etc.– But 0.1 – 1 km resolution to observe thunderstorm updrafts

and downdrafts

* Courtesy of: Fred Carr, Univ. Oklahoma


Tropopause (8~13 km)• Jet Stream

Mid Troposphere (2~8 km)• Location/intensity of short waves

PBL (Sfc~2 km)• Ageostrophic• Orographic• Temp, Moisture, Wind, Precipitation• Surface/sub-surface conditions

PBL has largest unmet need for improved observations

(assuming that next-generation satellite sensors measure V, T and q at needed resolutions and

precision above the PBL)

Critical to get forcing correct in PBL, and

short waves in troposphere

Tropopause

Mid-Troposphere

Planetary BoundaryLayer (PBL)

Courtesy of: Fred Carr, Univ. Oklahoma

What Additional Observations Are Needed? (source: NAOS)

Satellite imagery & soundings


The greatest need in future mesoscale observing capability is high vertical resolution of T, q and wind in the PBL.

Slight variations in these values will have a major impact on:

thunderstorm vs. severe thunderstorm vs. squall line vs. MCC,

and subsequent forecasts of flooding, winds, temperatures, etc.,

and consequent impacts on health, safety, agriculture, transportation, energy, etc.

~2kmNeed 100-200m resolution!


Why the PBL? (source: NAOS)


Diurnal Boundary-Layer Evolution (after Stull)

©Vaisala | date | Ref. code | Page 24

Urban Boundary Layer: Scales & Layers


Near-Surface Layer: Scales & Layers


1 mm 1 cm 1 m 10 m 100 m 1 km 10 km 100 km 1000 km

Horizontal grid spacing

ModelingGap

Raw

inso

nd

es

ACARS

RADARDaytime Boundary Layer

SfcObs

Building Urban Storm Fronts Synoptic

Surface Layer

Measurement Capabilities: Transport & Diffusion Scales

Slide courtesy Walter Bach, ARO


1 mm 1 cm 1 m 10 m 100 m 1 km 10 km 100 km 1000 km

Horizontal grid spacing

ModelingGap

Raw

inso

nd

es

ACARS

RADARNocturnal

Boundary Layer

SfcObs

Building Urban Storm Fronts Synoptic

Surface Layer

Measurement Capabilities: Transport & Diffusion Scales

Slide modified after Walter Bach, ARO


(MacDonald et al., 2001)

SCOS-97 mixing depths, September 4, 1997

Mixing Depth – Spatial and Temporal Variability

0300LST

1400LST

L.A. Basin

(Plate, 2004)


Emergence of Urban-Based Mesoscale Initiatives

• U.S. Weather Research Program PDT-10 on Urban Forecasting (1998)

• U.S. Weather Research Program PDT-11 on Air Quality Forecasting (2001) and subsequent AQF Workshop (2003)

• U.S. Weather Research Program Community Workshop on Multifunctional Mesoscale Observing Systems (2003)

• U.S. Environmental Protection Agency Recommendations on Air Quality Forecasting and the Role of Urban Testbeds (2004)

• Helsinki Mesoscale Testbed (in operation since 2005)

• U.S. National Academies’ Panel on Multi-Functional Mesoscale Networks (midway through an 18-month study; completion 1Q 2008)

• U.S. Multi-Agency New Study of Urban Meteorological Testbeds (ongoing; completion 1Q 2008)

• American Meteorological Society’s New Panel on Partnerships and Mesoscale Networks (midway through an 18-month study; no completion target as yet)

• Canadian Research on Improved Urban Weather and Air Quality Forecasting (started in 2006 a 3-Year Study)

• U.S. National Science Foundation Study on Urban Meteorology (started a 5-year study in 2006)

• Beijing Mesoscale Network (in advanced implementation stage)

• London Mesoscale Network (in early planning stage)


Common Themes from Four USWRP Workshops & PDTs

PDT-10 PDT-11 WKSHOP WKSHOPFUZ AQF AQF MESOMS

Impacts of visibility & icing on transportation X Improved understanding & forecasting of winter storms X X Improved understanding & forecasting of convective storms X X Improved understanding & measurement of clouds &cloud processes X X Intense/severe lightning X X PBL understanding and measurement X X X X Land surface processes X X X Mesoscale weather forecasting for emergency response X X X X Mesoscale weather forecasting for air quality forecasting X X X X Hydrological modeling X X Optimized observing system design for urban needs X X X X Data assimilation X X X X Uncertainty and predictability X X Tailor forecast and data products to user needs X X X X Improved access to data and forecast products X X X X Need for testbeds X X X Develop strong outreach programs to end users X

Themes


One Very Relevant Study of the US Weather Research Program

BAMS 86(7), 2005


Recommendations re: Modeling & Data Assimilation

Current observations are not sufficient for mesoscale applications. The following observations are needed to most effectively address deficiencies in current observing networks: More accurate precipitation rates with good quality control; Three-dimensional hydrometeor fields; Three-dimensional mass, wind, and moisture fields 10-km horizontal resolution in the lower troposphere 10-100 km in the upper troposphere; Three-dimensional cloud fields and cloud diabatic heating rate profiles; Daily land (sea) surface features Soil moisture and temperature profiles, Snow cover and depth, Land and sea-surface temperature (SST), Emissivity Vegetation type and state; Turbulent flow, fluxes, and stability measured from Earth’s surface to 2 km 15 min. intervals and 100-200m vertical resolution; PBL height and characteristics of convective rolls; Tropopause topology with 10 km horizontal resolution; O3, CO2, water vapor, & cloud distributions req’d for radiative transfer models;

Aerosols and chemical tracer concentrations

Observational Recommendations from the Modeling & Data Assimilation Community (mesoscale workshop)Observational Recommendations from the Modeling & Data Assimilation Community

• 3D high-resolution fie

lds

• Precipitation, hyrdometeors and clouds

• Surface characterization

• PBL structure

• Chemical species and PM

• Testbeds are crucial


Recommendations re: Nowcasting

Top mesonet recommendation:

Establish a national mesonetwork of surface stations. NOAA should take the lead to establish this network, and set standards for data quality. Resolution needed: <10-25km and 5-15min.

Remote sensing recommendations: Addition of dual polarization capability to the WSR-88D network. Pursue integration of other radars into the national radar network. Investigate improving boundary-layer coverage through the use of

closely spaced X-band radars. Vigorously pursue national expansion of the NOAA Profiler Network

with emphasis on boundary-layer observations. Test the utility of radar refractivity measurements to improve

nowcasting.

Observational Recommendations from the Nowcasting Community (mesoscale workshop)Observational Recommendations from the Nowcasting Community (from the Mesoscale Workshop)


Recommendations re: Nowcasting

Other priority recommendations: Conduct research aimed at using total lightning data to improve severe

weather warnings and nowcasts. Demonstrate added value of high-resolution water vapor fields for

improve nowcasting. Establish testbeds for very short period forecasting (0-6 hr, nowcasting)

of high-impact weather. Tasks should include: siting recommendations; identification of leveraged funding sources; identification of public/private partners; specification of nowcasting systems and products; involvement of potential clients and users; and conducting impact and benefits studies.

Observational Recommendations from the Nowcasting Community (mesoscale workshop)Observational Recommendations from the Nowcasting Community (from the Mesoscale Workshop)


Recent Supporting Studies of the USWRPTwo Other Relevant USWRP Studies on AQF

BAMS 87(2), 2006


BLD C&A M&M OAQF S&SI Total

Boundary-Layer Structure & Modeling 2 1 1 - 4

Surface-Atm. Interface & Emissions 1 2 3 1 - 7

Clouds & Aerosol Microphysics 2 3 2 2 - 9

Establish AQ Regional Testbeds 5 3 2 - - 10

Instrumentation & Measurements 4 3 5 2 - 14

Data Assimilation 1 2 2 1 - 6

Models & Modeling - 9 8 4 - 21

Forecaster & End-User Products - - - 2 1 3

Outreach - - - 1 10 11

85

Recommendations per Working GroupResearch Theme:

Organization of RecommendationsScope of AQF Workshop Recommendations

BLD = Boundary-layer Dynamics WGC&A = Clouds and Aerosols WGM&M = Measurements and Modeling WGOAQF = Operational Air Quality Forecasting WGS&SI = Stakeholders and Societal Impacts WG

Recommendations focus equally on measurement &

modeling

Recommendations focus equally on measurement &

modeling

©Vaisala | date | Ref. code | Page 44U+ extremely urgentU urgentI important

U+ extremely urgentU urgentI important

Some Specific Recommendations from the USWRP AQF Workshop (29 April - 1 May 2003)


Science

Measurement Technology & Environmental Prediction

Modeling

Computing

Observations

Improved atmospheric measurements are central to improved environmental analyses and forecasts


• Weather radar: reflectivity; velocity, polarization; refractivity

• Wind profilers: radar, sodar; lidar; tethersondes; aircraft

• Thermodynamic soundings: RAOBS, aircraft; tethersondes; lidar

• Lightning detection: CG; total• Radiometers: microwave -- scanning;

multi-wavelength• GPS receivers: precipitable water vapor --

column integrated; maybe slant path and 3D

• Surface mesonets: PTU; V; LW, SW, net radiation; energy & momentum fluxes

• Satellites: geostationary; POES; LEO

Candidate Measurement Systems


•Elevation angles between 0.5 and 20 degrees

•Earth surface curvature effect

•“Cone of silence” & “pyramid of silence”

•Much less coverage at the low levels/in PBL where features such as thunderstorm outflows, convergence boundaries are crucially important

•Resolution degrades further away from radar

•~75-85% of PBL is not observed


WSR-88D Radar Network Coverage – PBL Limitations

CONE OF SILENCE

PYRAMID OF

SILENCE

0.5deg

20deg


CASA

Price target equivalent to a mid-to-high-end automobile


Estimating Mixing Depth

Cn2

VerticalVelocity

SpectralWidth

Mixing Depth – Data and MethodsMixing Depth – Radar Wind Profiler

0 local time 24


Mixing Depth – Ceilometer vs. RAOB Sounding (2000)CT25K Backscatter 28-29-Mar-2000

Local Time (h)

Alt

itude (

m)

10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22 00

500

1000

1500

2000

2500

3000

0 5 100200400600800

100012001400160018002000Radiosonde Sounding 29-Mar-2000 @ 11:44

Potential Temperature (°C)

Alt

itude (

m)

102 103 1040200400600800

100012001400160018002000CT25K Backscatter 29-Mar-2000 @ 11:44

Backscatter (a.u.)

Alt

itude (

m)

1m

CT25K BSL


Mixing Depth – Ceilometer vs. RAOB Sounding (2006)


Summary of Selected Mesoscale/Urban Challenges

PBL observations with high vertical and temporal resolution radar wind profilers lidars & laser ceilometers x-band radars aircraft

Dynamic characterization of land surface

Acquire & assimilate 4D meteorological and chemical data

High-resolution surface networks: <10km and 5min resolution

Augmentation of weather radar network dual polarization radars of opportunity high-density, low-power radar networks total lightning observations – merge with radar data adaptive radar calibration

Testbeds -- a vehicle to evaluate alternative measurement, modeling and implementation strategies

Optimal network design


Some Definitions

APPLICATION

Mesoscale networks measure the three-dimensional, time-dependent structure of the lower atmosphere using an integrated observing system that incorporates in situ and remote sensing systems, deployed on/from the ground and aloft.

“Mesonets” are a subset of mesoscale networks that consist of high-density surface stations.

Mesoscale networks measure the three-dimensional, time-dependent structure of the lower atmosphere using an integrated observing system that incorporates in situ and remote sensing systems, deployed on/from the ground and aloft.

“Mesonets” are a subset of mesoscale networks that consist of high-density surface stations.


General applications

• Analysis/description of current atmospheric state – research or ops

• Nowcasting/very short-range forecasting (0+ to ~2 hrs)

• Short-range mesoscale prediction (~3 to 48 hrs)

Site of interest

Are

a (r

el.)

analysis

mesoscale prediction

nowcasting

Schematic

illustrationSchematic

illustration

Time (rel.)

As the timescale of the prediction increases, so does the commonality of the observing systems needed to make the prediction (i.e. they become less application-specific).

As the timescale of the prediction decreases -- toward analysis and short- term nowcasting – the observing requirements become more application-specific

As the timescale of the prediction increases, so does the commonality of the observing systems needed to make the prediction (i.e. they become less application-specific).

As the timescale of the prediction decreases -- toward analysis and short- term nowcasting – the observing requirements become more application-specific


Mesoscale Weather Forecasting -- Testbeds

Testbed Definition: “A working relationship in quasi-operational framework among forecasters, researchers, private-sector, and government agencies aimed at solving operational and practical regional problems with a strong connection to end-users.”


Testbed Criteria

A successful testbed must satisfy the following criteria: Address the detection, monitoring, and prediction of regional

phenomena of particular interest Define expected outcomes Provide special observing networks needed for pilot studies and

research Define strategies for achieving the expected outcomes Engage experts in the phenomena of interest Involve stakeholders in planning, operation, and evaluation of the

testbeds Expedite R2O: transitioning research to operations


Testbed Concept

Testbeds provide the infrastructure for transitioning from R&D to operations. Testbeds need the flexibility to test many new ideas, the expertise to judge which of them are viable, and the infrastructure to harden the sensors, algorithms and models that will generate new products for operations.


Status of some Mesoscale Testbeds

• Helsinki Testbed Phase I (observations) started August 2005; Phase II (applications) started August 2007

• Beijing Olympics 2008 enhanced mesoscale observing-and-forecasting underway

• Shanghai 2010 World Expo enhanced meso- and micro-scale multi-functional observing-and-forecasting system in advanced planning

• U.S. preparations/planning underway• DHS – Homeland Security limited urban nets in New York and WDC• OFCM urban testbeds under consideration• Multi-agency planning in early stage – NRC/BASC study (completion early

2008)


Two Approaches to Designing Networks

Designing

Mesoscale

Meteorological

Observing

NetworksEmpirical

Methods

(current

state-of-the-art)

Analytical

Methods

(in development)

Team of experts (Wx & AQ):• Forecasters• Modelers• Observationalists• Other ‘stakeholders’

Numerical tools:• OSSEs• OSEs• Data denial experiments• Observational testbeds

mesoscale observing challenges: one perspective with emphasis on the urban zone presentation to the:...

Documents

vaisala date

code page

inland city slide

regions wfd slide

colorado slide

growth of megacities

world population

developed regions source