Earth’s Changing Climate

The Intergovernmental Panel on Climate Change (IPCC) issued an important special report yesterday on climate change.  In the accompanying press release, they state the following:

    • Limiting global warming to 1.5°C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities.  Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This  means that any remaining emissions would need to be balanced by removing CO2 from the air.
    • This report will be a key scientific input into the Katowice Climate Change Conference in Poland in December, when governments review the Paris Agreement to tackle climate change.
    • We are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice.
    • Warming of 1.5ºC or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems.

In the Summary for Policymakers, the IPCC states that “warming from anthropogenic emissions from the pre-industrial period to the present will persist for centuries to millennia and will continue to cause further long-term changes in the climate system, such as sea level rise, with associated impacts.”

This last point is very important.  Even if humanity disappeared from the face of the Earth tomorrow, it will take centuries to millennia for greenhouse gases in our atmosphere to return to pre-industrial levels.

Richard Wolfson, Professor of Physics at Middlebury College in Middlebury, Vermont, states in his excellent 2007 video course, “Earth’s Changing Climate” (The Great Courses, Course No. 1219),

The atmosphere, living things, soils, and surface ocean waters all represent short-term carbon reservoirs.  Cycling among these reservoirs occurs mostly on relatively short time scales.  In particular, a typical carbon dioxide molecule remains in the atmosphere only about five years.  But the rapid cycling of carbon through the atmosphere-biosphere-surface ocean system means that any carbon added to that system remains there much longer—for hundreds to thousands of years. Because the added carbon cycles through the atmosphere, the level of atmospheric carbon dioxide goes up and stays up for a long time.

We’ve known about this aspect of climate change for a long time.  It is based on solid science.  Any action we take now, either positive or negative, will affect Earth’s environment many generations into the future.

I know of no better introduction to climate science than Richard Wolfson’s video course.  Even though it was produced 11 years ago, it is still completely relevant.

Earth’s Changing Climate, The Great Courses, Course No. 1219

Help Save WWV and WWVH!

Read these articles about the proposed elimination of radio time services WWV (Fort Collins, Colorado) and WWVH (Kekaha, Kauai, Hawaii) in 2019:

https://www.voanews.com/a/time-may-be-running-out-for-millions-of-clocks/4554376.html

https://www.nist.gov/director/fy-2019-presidential-budget-request-summary/fundamental-measurement-quantum-science-and

And please sign this petition by September 15:

https://petitions.whitehouse.gov/petition/maintain-funding-nist-stations-wwv-wwvh

WWV continuously broadcasts time signals at 2.5, 5, 10, 15, and 20 MHz, and WWVH does the same at 5, 10, and 15 MHz.

There are many uses for these radio stations.  For example, I have a shortwave radio in my observatory and use the WWV voice time broadcasts on 2.5, 5, and 10 MHz to make sure my GPS clock is properly synchronized, and also use it to set my computer clocks accurately and well as my wristwatch.

WWV and WWVH are an important and reliable “low tech” backup to the Global Positioning System (GPS) satellite constellation which can be used to derive accurate times.

Well over 50 million devices use the 60 kHz signal provided by WWVB to allow them to maintain accurate time, and eliminating this particular service would be devastating.  Whether or not shutting down WWVB is part of the proposed budget cuts remains to be seen.

These U.S. Government radio stations have been announcing accurate time since World War II.  We must do all we can to ensure their continued operation.

March for Our Lives

I am so very proud of what hundreds of thousands of Americans of all ages did today, marching in hundreds of anti-gun-violence rallies all across our nation.  I’m especially proud of the students.  We had a huge group of marchers in Mineral Point, Wisconsin (students included), and I was glad I participated.

I do not want to live in a country where everyone is armed to the teeth.  You know, you have to decide what kind of a world you want to live in and then work towards that goal, no matter how difficult.

Paul McCartney at a March for Our Lives event in New York City

I was devastated and angry when John Lennon was shot to death in New York in 1980 outside his apartment building by a very disturbed man (it is almost always a man, isn’t it?).  I mean, who the hell would kill a musician?  I will never get over it On that day (and many times since), I decided “enough is enough”.  Gun ownership should be a privilege that has to be earned, not a right.  And weapons of war do not belong in the hands of private citizens—ever.  If that involves repealing the Second Amendment to the United States Constitution, then so be it.  But “we the people” never get a chance to vote on gun issues, do we?

If gun owners in this country can’t support much stricter and sensible gun laws, then maybe we should peacefully go our separate ways.  Gun lovers can have their country (a dystopia, really), and the rest of us can live somewhere else.  I would support a civil separation, but never a civil war.  (Besides, we know what side has most of the guns.)

“The young do not know enough to be prudent, and therefore they attempt the impossible, and achieve it, generation after generation.”

– Pearl S. Buck (1892-1973)

Illumination Levels: Then and Now

The following excerpts are from the 1911 and 1925 editions of A Text-Book of Physics by Louis Bevier Spinney, Professor of Physics and Illuminating Engineering at Iowa State College (now Iowa State University) in Ames, Iowa.

From the 1911 edition…

ILLUMINATION

516. The intensity of illumination of any surface is defined as the ratio of the light received by the surface to the area of the surface upon which the light falls.  A unit of intensity which is oftentimes employed is known as the foot candle, and is defined as the intensity of illumination which would be present upon a screen placed at a distance of one foot from a standard candle.  The meter candle is a unit of intensity which is employed to some extent.

The table below gives a number of values of illumination such as are commonly observed, the intensity of illumination being expressed in foot candles.

Suitable for drafting table    .    .    .    .    .    5 to 10

Suitable for library table   .    .    .    .    .   .    3 to 4

Suitable for reading table   .    .    .    .    .   .  1 to 2

Required for street lighting   .    .    .    .    .  0.05 to 0.60

Moonlight (full moon)    .    .    .    .    .    .   .  0.025 to 0.03

 

And from the 1925 edition…

ILLUMINATION

532.  The eye has a remarkable power of adaptation.  In strong light the pupil contracts and in weak light expands, so that we are able to use our eyes throughout a range of illumination which is really quite astonishing.  However, the continued use of the eyes under conditions of unfavorable illumination causes discomfort, fatigue, and even permanent injury.  Experiment and experience show that eye comfort, efficiency, and health considerations demand for each kind of eye work a certain minimum illumination.  Some of these illumination values taken from tables recently compiled are given below.

FOOT-CANDLES

Streets    .    .    .    .    .    .    .    .    .     .    .    .    .    .    1/20 to 1/4

Living rooms; Halls and passageways    .    .    1 to 2

Auditoriums; Stairways and exits;
Machine shops, rough work    .     .    .    .    .    .  2 to 5

Classrooms; Laboratories; Offices;
Libraries; Machine shops, close work    .    .    5 to 10

Engraving; Fine repairing work; Drafting;
Sewing and weaving, dark goods  .    .    .    .     10 to 20

 

By comparing the 1911 and 1925 data with the illumination levels recommended today by IESNA, we can see that recommended light levels for streetlighting have increased anywhere from 40% to 380% since 1925.  A cynic might say that we need more light than our ancestors did to see well at night.  As you may have noticed, light levels have been steadily creeping upward, everywhere, over the last few decades.

Recommended Illumination Levels for Streetlighting

Year        Minimum    Average    Maximum

1911             0.05                ???               0.60

1925           0.05               0.25               ???

1996          0.07                1.20               ???

Have you ever noticed how well you can see at night when the full moon is lighting the ground?  The full moon provides surprisingly adequate non-glaring and uniform illumination at just 0.03 footcandles!  For inspiration, take a look at the following text from an Ames, Iowa city ordinance, dated July 8, 1895:

“The said grantees shall keep said lamps in good condition and repair, and have the same lighted every night in the year from dark until midnight, and from 5:00 a.m. until daylight, except such moonlight nights or fractions of the same as are not obscured by clouds, and as afford sufficient natural light to light the streets of said city.”

This was originally published as IDA Information Sheet 114 in November 1996, and authored by David Oesper.

Dodgeville Street Project Proposals

As illustrated below, a lot of drivers in Dodgeville take a dubious “short cut” from King St. to Iowa/Bequette by way of W. Leffler instead of taking King St. all the way to Iowa/Bequette.  Most of the people taking this short cut are leaving Lands’ End and heading to their homes in the Madison metro area.  These folks are not Dodgeville / Iowa County taxpayers.  Here’s the problem.  W. Leffler has been beat all to hell and is badly in need of resurfacing.  All that Lands’ End traffic has contributed mightily to the degradation of W. Leffler.  Now, as a bicycle commuter trying to get from Lands’ End to most of the rest of Dodgeville (always a dangerous proposition), it makes sense to use W. Leffler to minimize the amount of time I have to ride my bike on busy King St. and very busy Iowa/Bequette.  But W. Leffler is so broken up that for safety reasons I need to ride near the middle of the road—but a steady stream of vehicles takes the short cut down W. Leffler instead of staying on King St. up to convenient entrance ramp to Iowa/Bequette.  It is a no-win situation for Dodgeville bicyclists.  One solution would be to have W. Leffler dead end at King St. with only a bike-path connector between King St. and W. Leffler, though I suspect that would be quite unpopular in our auto-centric community.  Another solution would be to resurface W. Leffler and never let it degrade this much again.  Is that too much to ask?  It is a short street, after all.

The Lands’ End Shortcut to the Madison Metro Area

I’m not a big fan of roundabouts, but if ever there was a case for one it would be at the intersections of Iowa/Bequette, N. Main, E. Spring, and W. Spring.  In my crude map overlay below, it looks like one building would probably have to be removed.  The roundabout would need to be designed to easily accommodate the comings and goings of fire trucks from the nearby fire station.  Presently, this “octopus” of an intersection is dangerous, and I completely avoid ever making a left turn there.  Why not prohibit all dangerous left turns at these intersections by installing a roundabout where every turn will be a right turn?

Where a roundabout is needed in Dodgeville

Greater Intelligence

Allen Telescope Array; Photo Credit: Seth Shostak, SETI Institute, 2006
Calvin and Hobbes, November 8, 1989, by Bill Watterson

Could we please replace our idiocracy with a meritocracy?  Before it’s too late?  With checks and balances, of course.  Let’s raise the bar across our society instead of continuing to appeal to the lowest common denominator.  Our very survival depends upon it.

What Is and What Might Have Been

We continue our series of excerpts (and discussion) from the outstanding survey paper by George F. R. Ellis, Issues in the Philosophy of Cosmology.

Thesis E2: We cannot take the nature of the laws of physics for granted.
One cannot take the existence and nature of the laws of physics (and hence of chemistry) as unquestionable in cosmology—which seems to be the usual habit in biological discussions on the origin and evolution of life.  This is in stark contrast to the rest of science, where we are content to take the existence and nature of the laws describing the fundamental behaviour of matter as given and unchangeable.  Cosmological investigation is interested in the properties of hypothetical universes with different physical behaviour.  Consideration of ‘what might have been’ is a useful cosmological speculation that may help throw light on what actually is; this is a statement of the usefulness of ‘Gedanken experiments‘ in cosmology.

Practical science, engineering, and technology are prescriptive.  If we do a, we know from experience that b will occur.  Using the laws of physics, we can predict the location of the Moon as a function of time, put a spacecraft in orbit around Saturn, or build a light bulb that will illuminate.  Though we may be curious, we are not required to know why or how these laws exist—or how they might have been different—only that they do work, time and time again.

Cosmology, though firmly rooted in science, is different.  We are passive observers in a very large and very old universe, and there is no absolute guarantee that the laws of physics that work for us so well in the here and now apply to all places and at all times.  We must attempt to understand the laws of physics in a larger context that does involve some well-reasoned and reasonable speculation.

“Not only does God … play dice, but He sometimes confuses us by throwing them where they can’t be seen.” – Stephen Hawking

“Sometimes attaining the deepest familiarity with a question is our best substitute for actually having the answer.” – Brian Greene

In politics, governance, sociology, and philosophy, too, I would submit to you that consideration of “what might have been” is useful in helping us to understand what actually is.  Such reflection, en masse, might even lead to substantive change.

“Why is it that here in the United States we have such difficulty even imagining a different sort of society from the one whose dysfunctions and inequalities trouble us so?  We appear to have lost the capacity to question the present, much less offer alternatives to it.  Why is it so beyond us to conceive of a different set of arrangements to our common advantage?” – Tony Judt

Getting back to cosmology, however, for the moment…

Indeed if one wants to investigate issues such as why life exists in the universe, consideration of this larger framework—in essence, a hypothetical ensemble of universes with many varied properties—is essential (this is of course not the same as assuming an ensemble of such universes actually exists).  However, we need to be very cautious about using any claimed statistics of universes in such a hypothetical ensemble of all possible or all conceivable universes.  This is usually not well defined, and in any case is only relevant to physical processes if either the ensemble actually exists, rather than being a hypothetical one, or if it is the outcome of processes that produce well-defined probabilities—an untestable proposal.  We can learn from such considerations the nature of possible alternatives, but not necessarily the probability with which they might occur (if that concept has any real meaning).

It is easy to imagine a universe without life.  But we obviously do not live in such a universe.  There may be other universes devoid of life.

For the more thoughtful among us, it is easy to imagine a civilization without war, guns, violence, extrinsic suffering1 caused by others, or deprivation.  Obviously, we do not live in such a society.  But how can we say it is impossible, or even improbable?  It would be easy to find many millions of people in the world even today that would never fight in a war, would never own or use a gun, who would never resort to violence, who would never cause others to suffer, and who would make eliminating deprivation and poverty a top priority.  The question for the scientists is: what is wrong with the rest of us?

1Extrinsic suffering is suffering caused by others or circumstances completely outside of one’s control.  Intrinsic suffering, on the other hand, is self-inflicted—through our own failings, poor judgement, or mistakes that we make.

Growing Older

As we grow older,
That which is older grows upon us.
Time accelerates,
And the world seems a smaller place.

The years go by like months,
The months go by like weeks,
The weeks go by like days,
The days go by like hours,
And the hours go by like minutes.

And our world which in our youth was all that we knew
Slowly reveals itself to be a surprisingly alien place,
Full of centuries of hard work, unlikely events, and compromise:
The world could be a very different (and better) place,
Even within the confines of human nature.

Taken to its natural conclusion
Were we each to live for millennia, perhaps longer
We would find eternity in an instant
And infinity at the door.

David Oesper

References
Ellis, G. F. R. 2006, Issues in the Philosophy of Cosmology, Philosophy of Physics (Handbook of the Philosophy of Science), Ed. J. Butterfield and J. Earman (Elsevier, 2006), 1183-1285.
[http://arxiv.org/abs/astro-ph/0602280]

Dark Sky Community Prospectus

  1. Rationale
    1. A small community (hereafter referred to as a dark sky community) can thrive without the need for streetlights or any other dusk-to-dawn lighting
    2. A dark sky community would appeal to people who value the night sky and a natural nighttime environment
    3. It will probably be many years before the majority of people will accept life without dusk-to-dawn outdoor lighting
    4. A dark sky community must be located far enough away from neighboring communities and other significant light sources that the night sky and nighttime environment will not be adversely affected, either now or in the foreseeable future
    5. It is better to live in community than in isolation
  2. Community Attributes
    1. A dark sky community should be multi-generational, but since rural employment options are limited, moving to a dark sky community may be easier for retired or semi-retired folks
    2. A dark sky community should be affordable, with a variety of housing options (units that can be rented, for example)
    3. An observatory commons area should be developed for observing and include more than one observatory for use by members of the community
    4. The dark sky community should engage in an ambitious educational outreach program, including the operation of an astronomy resort and astro-tourism business
    5. The business end of the community should be a nonprofit corporation or cooperative that operates the astronomy resort and rental properties
    6. The community should share resources as much as possible, freeing residents from the financial burden of having to individually own everything they need or use
    7. The dark sky community should engage in an ambitious program of collaborative astronomical research and data collection, working collaboratively within the community and with amateur and professional astronomers outside the community
  3. Community Location
    1. The most affordable option would be to “convert” an existing rural subdivision or small town into a dark sky community, current residents willing, of course!
    2. The best location for a dark sky community would be within, or adjacent to, a protected natural area such as a state or national park
    3. Recognizing that there would be distinct advantages in siting a dark sky community reasonably close to a town or city with medical facilities, it would be best (for astronomical reasons) for the dark sky community to be located southeast or southwest of the larger community
  4. Philosophy
    1. In an age of technological wonders such as digital imaging, computer-controlled telescopes, remote observing, and space astronomy, we recognize that there is still value in the experience of “firsthand astronomy” both for ourselves and our guests

For greater detail, see my astronomy village proposal for Mirador Astronomy Village.  I welcome your comments and ideas here.

Renters and Flood Plains

The catastrophic flooding in Houston brings back terrible memories of  the flood I experienced during the early morning hours of Tuesday, May 26, 2015 when my apartment in the Meyerland area of Houston took on three feet of water and I lost most of my belongings including my car.  There was no warning that the Brays Bayou would leave its banks that night.  My Meyergrove apartment has flooded again twice since I left Houston in September 2015: once on April 18, 2016, and again this weekend.  This frequency of flooding is unprecedented in that area of Houston.

Flood scene from 2nd floor balcony of my apartment building during morning twilight, May 26, 2015.

Everyone with a ground floor apartment lost most of their belongings in my apartment complex during the Memorial Day Weekend 2015 flood.  No one I talked to had flood insurance, and everyone had renter’s insurance that did not cover their flood damage, so they lost a lot.

Brays Bayou from the 2nd floor balcony of my apartment building, morning of May 26, 2015.

Which brings up an important point.  Why are there not laws to require lessors to disclose to renters when the apartment or house they are renting sits in a flood plain?  If the lessor has flood insurance on their property, then they should be required to inform their tenants of that fact and clearly communicate that the tenant should purchase flood insurance in addition to their renter’s insurance.  After all, when you are buying a house, you cannot get a home loan unless you purchase flood insurance if you are living in a flood-prone area.  Why do not renters have the same protection?

Perhaps there are other areas of the country where landlords have to disclose to their renters if they will be living in a flood plain, but there appears to be no such protection for renters in the state of Texas.

 

 

Where Voters Rejected Trump

The United States has never had a president like Donald Trump.  And hopefully we will never have a president like him again.  Regardless of your political persuasion, this man has neither the experience nor the temperament to be a public servant, and he should never have been elected.

In the map below, you will find the 143 counties (or county equivalents) where Hillary Clinton received at least twice as many votes as Trump in the 2016 Presidential election.  Counties in red have a lower population density than Iowa County, Wisconsin, and counties in blue a higher population density.  Even though Iowa County, WI did not make the list, I am happy to say there were 1.39 Clinton voters for every Trump voter in this rural county in a state where Trump won (just barely) a majority of the votes.

Let us first look at the rural counties that voted heavily against Trump—by a 2 to 1 margin or better.  All but 5 of the 40 rural counties have African-American, Hispanic, or Native American majorities.

The seventeen rural counties with African-American majorities (67.5% to 85.8%) are

Alabama
Bullock County
Greene County
Lowndes County
Perry County
Sumter County
Wilcox County

Georgia
Hancock County

Mississippi
Claiborne County
Holmes County
Humphreys County
Jefferson County
Noxubee County
Quitman County
Sharkey County
Tunica County
Wilkinson County
South Carolina
Allendale County

The per capita income in these counties with African-American majorities range from a low of $11,972 in Holmes County, Mississippi to $18,429 in Lowndes County, Alabama.  The average for all seventeen counties is $14,344.

The twelve rural counties with Hispanic majorities (56.7% to 94.6%) are


New Mexico
Mora County
Rio Arriba County
San Miguel County
Taos County

Texas
Brooks County
Dimmit County
Duval County
Jim Hogg County
Presidio County
Willacy County
Zapata County
Zavala County


The per capita income in these counties with Hispanic majorities range from a low of $11,413 in Willacy County, Texas to $22,358 in Taos County, New Mexico.  The average for all twelve counties is $17,171.

And the six rural counties with Native American majorities (75.4% to 92.8%) are

Arizona
Apache County

New Mexico
McKinley County

North Dakota
Sioux County

South Dakota
Oglala Lakota County
Todd County

Wisconsin
Menominee County

The per capita income in these counties with Native American majorities range from a low of $9,150 in Oglala Lakota County, South Dakota to $15,557 in Sioux County, North Dakota.  The average for all six counties is $12,738.

Now let’s look at the five remaining rural counties that voted heavily against Trump in the 2016 general election.

California
Mendocino County

Colorado
Pitkin County
San Miguel County

Washington
Jefferson County
San Juan County

The per capita income in these counties range from a low of $24,059 in Mendocino County, California to $55,519 in Pitkin County, Colorado.  The average for all five counties is $37,517.

Finally, here is a list of counties (and county equivalents) than have a higher population density than Iowa County, Wisconsin, where Hillary Clinton received at least twice as many votes as Donald Trump.  These are listed by state, with the largest city in each county in parentheses.

Alabama
Dallas County (Selma)
Macon County (Tuskegee)

Arizona
Santa Cruz County (Nogales)

California
Alameda County (Oakland)
Contra Costa County (Concord)
Imperial County (El Centro)
Los Angeles County (Los Angeles)
Marin County (San Rafael)
Monterey County (Salinas)
Napa County (Napa)
San Francisco County (San Francisco)
San Mateo County (Daly City)
Santa Clara County (San Jose)
Santa Cruz County (Santa Cruz)
Sonoma County (Santa Rosa)
Yolo County (Davis)

Colorado
Boulder County (Boulder)
Denver County (Denver)

District of Columbia

Florida
Broward County (Fort Lauderdale)
Gadsden County (Quincy)

Georgia
Clarke County (Athens)
Clayton County (Forest Park)
DeKalb County (Brookhaven)
Dougherty County (Albany)
Fulton County (Atlanta)

Hawaii
Hawaii County (Hilo)
Kauai County (Kapaʻa)
Maui County (Kahului)

Illinois
Cook County (Chicago)

Iowa
Johnson County (Iowa City)

Kansas
Douglas County (Lawrence)

Louisiana
Orleans Parish (New Orleans)

Maryland
Howard County (Columbia)
Montgomery County (Germantown)
Prince George’s County (Bowie)
Baltimore City (Baltimore)

Massachusetts
Berkshire County (Pittsfield)
Dukes County (Edgartown)
Franklin County (Greenfield)
Hampshire County (Amherst)
Middlesex County (Lowell)
Nantucket County (Nantucket)
Suffolk County (Boston)

Michigan
Washtenaw County (Ann Arbor)
Wayne County (Detroit)

Minnesota
Hennepin County (Minneapolis)
Ramsey County (Saint Paul)

Mississippi
Coahoma County (Clarksdale)
Hinds County (Jackson)
Leflore County (Greenwood)
Sunflower County (Indianola)
Washington County (Greenville)

Missouri
St. Louis City (St. Louis)

New Jersey
Camden County (Camden)
Essex County (Newark)
Hudson County (Jersey City)
Mercer County (Hamilton Township)
Union County (Elizabeth)

New Mexico
Santa Fe County (Santa Fe)

New York
Bronx County (New York City: The Bronx)
Kings County (New York City: Brooklyn)
New York County (New York City: Manhattan)
Queens County (New York City: Queens)
Tompkins County (Ithaca)
Westchester County (Yonkers)

North Carolina
Durham County (Durham)
Hertford County (Ahoskie)
Orange County (Chapel Hill)

Ohio
Cuyahoga County (Cleveland)

Oregon
Benton County (Corvallis)
Multnomah County (Portland)

Pennsylvania
Philadelphia County (Philadelphia)

South Carolina
Orangeburg County (Orangeburg)
Richland County (Columbia)
Williamsburg County (Kingstree)

Texas
Cameron County (Brownsville)
El Paso County (El Paso)
Hidalgo County (McAllen)
Maverick County (Eagle Pass)
Starr County (Rio Grande City)
Travis County (Austin)
Webb County (Laredo)

Vermont
Addison County (Middlebury)
Chittenden County (Burlington)
Lamoille County (Morristown)
Washington County (Barre)
Windham County (Brattleboro)
Windsor County (Hartford)

Virginia
Arlington County (Arlington)
Fairfax County (Herndon)
Alexandria City (Alexandria)
Charlottesville City (Charlottesville)
Falls Church City (Falls Church)
Hampton City (Hampton)
Norfolk City (Norfolk)
Petersburg City (Petersburg)
Portsmouth City (Portsmouth)
Richmond City (Richmond)
Williamsburg City (Williamsburg)

Washington
King County (Seattle)

Wisconsin
Dane County (Madison)
Milwaukee County (Milwaukee)

References