Marswatch Electronic Newsletter: May 1997


From: jimbo@marswatch.tn.cornell.edu (Jim Bell) (by way of Jan Wee <jwee@mail.arc.nasa.gov>)
Subject: Marswatch Electronic Newsletter: May 1997
Date: Fri, 23 May 1997 11:00:00 -0500


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      THE INTERNATIONAL MARSWATCH ELECTRONIC NEWSLETTER
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             Volume 2; Issue 4 (file imw.may97)
                       May 22, 1997
                     Circulation: 762

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Friends of Mars,

Items in this (woefully late and much too large) Marswatch newsletter:

CONTENTS-------------------------------------------------------------------
-                                                                         -
-  Latest HST images of Mars: Chaotic climate!                            -
-  Schedule for next HST Mars images                                      -
-  Online Mars image archive a spectacular success!                       -
-  Announcement for Mars Telescopic Observations Workshop 2               -
-  Leonard Martin  1930 - 1997                                            -
-  Detailed HST Mars press release text                                   -
-  Additional information on Mars Workshop                                -
-                                                                         -
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Latest HST images of Mars: Chaotic climate!
-------------------------------------------
Recent HST images of Mars from March 1997 have just become available in a
press release from the Space Telescope Science Institute. These images,
combined with recent microwave telescopic results, indicate that the
Martian climate appears to oscillate between two primary states: a
cold, cloudy, dust-free climate (like we've seen over the past year)
dominates when the planet is at its farthest from the Sun, while a warmer, 
dustier climate dominates when the planet is closer to the Sun. Some
additional explanatory text is attached below, and the images can be
seen at the URL:

http://oposite.stsci.edu/pubinfo/PR/97/15.html


Schedule for next HST Mars images
---------------------------------
Also, please note that the next series of Hubble Space Telescope
observations of Mars will be obtained on June 4 and between June
26 to 29 (the exact dates and times are yet to be determined).
These observations are the beginning of an extensive set of images
designed to provide crucial support for the Mars Pathfinder landing
on July 4th.  As always, supporting groundbased visual observations, 
photographs, drawings, or CCD images of Mars shortly before, during, and 
shortly after this time period could be extremely helpful in interpreting 
the HST data.  If you are able to obtain observations, please email your 
results or upload them using the instructions at the URL:

http://mpfwww.jpl.nasa.gov/mpf/marswatch_ftp.html


Online Mars image archive a spectacular success!
------------------------------------------------
As of this writing, hundreds and hundreds of amateurs and professionals have
uploaded spectacular photographs, drawings, CCD images, and even videos of
Mars as viewed during 1996-97.  Images from September 1996 through May 1997
can be viewed and downloaded from this JPL-based archive. My informal survey
of the archive shows that there are extended time periods when Mars was
imaged every day for many days in a row, or multiple times per day from
different locations. Data have arrived from all over the U.S. and from many
observers in Canada, Europe, South America, and Asia. This has been a truly
spectacular success in terms of internation amateur-professional collaboration!
Please visit the archive and feel free to download some of these spectacular
views of the Red Planet!  The URL is:

http://mpfwww.jpl.nasa.gov/mpf/marswatch_images.html


Announcement for Mars Telescopic Observations Workshop 2
--------------------------------------------------------
We would like to announce that a workshop of Mars telescopic
observers and spacecraft remote sensing scientists is being planned
for October in Tucson Arizona. The workshop will be a small, focused
gathering of amateur and professional Mars researchers, organized by
Dr. Ann Sprague of the Lunar and Planetary Laboratory and sponsored by
the Lunar and Planetary Institute in Houston.  Anyone interested in
attending or presenting some of their results should read the attached
information below and get your name and address put onto the mailing 
list for future notifications.


Leonard Martin  1930 - 1997
---------------------------
We regret to report that Leonard Martin, a long time member of the 
planetary sciences community, passed away suddenly and unexpectedly on 
April 7.

Just as Lowell Observatory is instinctively associated with the study of 
Mars, over the last two decades Mars research at Lowell was synonymous 
with Leonard Martin.  Leonard began his observational career in the 
International Planetary Patrol, a globe-circling network of observatories 
which provided continuous photographic monitoring of Mars near its 
oppositions.  During the late 1970's, Leonard coordinated ground based 
observations with several Viking global imaging sequences, revealing 
detailed structures for clouds and albedo features detected telescopically.  
As interest in Mars waned following Viking, Leonard was able to preserve 
Lowell's photographic record of Mars oppositions with the support of the 
National Geographic Society and continued the series of airbrushed albedo 
maps produced in collaboration with USGS.  For the last several 
oppositions Leonard directed a series of multispectral CCD observations at 
Lowell Observatory, the most recent of which were obtained in February.

Although Leonard was a firm believer in the value of the historical record in 
providing a context for interpretation of spacecraft images, he always 
emphasized the temporal and geographical limitations and biases of 
telescopic as well as spacecraft data.  He liked to have time to savor and 
assimilate new observations and was happiest professionally when he was 
pouring over Viking images or sets of telescopic photos.  Such activities led 
at one time to his discovery of an unexpected group of dust storms in 
Echus Chasma and, later, to his careful compilation of the historical record 
of dust activity on Mars.  Since 1990 Leonard was heavily involved in 
Hubble Space Telescope Mars observations and contributed to several 
discoveries based on the WFPC images.  Leonard's many papers based on 
the photographic record revealed to many of us (whose impressions of Mars 
were derived mainly from spacecraft images) that the planet is a changing, 
dynamic system and that observations of a small group of years, however 
detailed, did not reveal its entire nature.   His quiet, but persistent
voice lent a tone of reality to many "Mars debates," and his
contributions invariably 
helped to advance our understanding of Mars.  His encouragement and 
mentoring of younger colleagues started many of us on our way to careers 
in Mars research.

Leonard Martin finally was forced to surrender his active role at Lowell 
Observatory early this year because of health problems.  He and his wife, 
Claudia, moved to Bend, Oregon, where the elevation and climate would be 
more beneficial to his health and he would still be able to participate in his 
favorite avocation, skiing.  He was not giving up on active participation in 
HST and other programs, however, and was in the process of establishing 
Internet connectivity in Bend in order to preserve his active participation in 
Mars research.  

His familiarity with diverse groups of Mars data was unmatched, and his 
role in the community will not be easily filled.   He was the last of a 
prestigious chain of telescopic observers of Mars at Lowell, and "his like 
will not soon be seen again."  Leonard Martin will be deeply missed by all 
of us who were privileged to know and work with him.

(tribute written by Phil James, Jim Bell, Todd Clancy, and Steve Lee)



Attachment #1: Recent Mars Press Release:
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MARS' CHAOTIC CLIMATE

If you think the weather on Earth is unpredictable, try living on Mars. One
week, the sky is pink and cloudless, filled with windblown dust raised from
the rusty Martian surface. By Martian standards, it's warm, about minus 40
degrees Fahrenheit. Then, in a matter of days, the dust is swept from the
atmosphere, temperatures plummet 40 degrees, and brilliant water ice clouds
appear against a dark blue sky.

Dramatic weather changes like these may not seem very different from a batch
of severe thunderstorms passing through your home town, but for Mars these
changes can sweep over the entire planet every week. It appears that Mars'
roller coaster-like weather is more chaotic and unpredictable than
scientists first thought. Observations by the Hubble Space Telescope and the
National Radio Astronomy Observatory (NRAO) radio telescope at Kitt Peak,
Ariz., show that the atmosphere of Mars is more complex and variable than
the picture revealed by the Viking and Mariner 9 orbiters. These spacecraft
collected information from the planet in the 1970's and painted a fairly
one-dimensional picture of Mars' climate. Images snapped by the orbiters
revealed huge dust storms spreading throughout the entire atmosphere when
Mars was closest to the sun (perihelion). These dusty conditions continued
to dominate the planet's climate when it was farthest from the sun
(aphelion). (Perihelion and aphelion occur every Mars year, which equals two
Earth years. Aphelion occurs in northern summer, perihelion in southern
summer.)

But information captured by Hubble and NRAO show that Mars is more often
cloudy than dusty, experiencing abrupt planet-wide swings between dusty and
hot and cloudy and cold. A state of emergency would be declared on Earth if
an ice or dust storm blanketed the entire planet.

These shifts in climate are driven by three important factors: Mars' thin
atmosphere, its elliptical orbit around the sun, and strong climatic
interactions between dust and water ice clouds in the atmosphere. Mars'
atmosphere is so thin that it weighs less than 1 percent of Earth's
atmosphere. Because Mars' atmosphere is so paper-thin and there are no
oceans to store up heat from the sun, the planet's temperatures respond more
quickly and intensely to surface changes and atmospheric heating by the sun.
There are also much larger annual changes in sunlight falling on Mars than
on Earth, because Mars' distance from the sun varies by 20 percent in its
orbit around the sun every two years.

Mars' elliptical orbit leads to planet-wide changes in atmospheric and
surface temperatures over the course of a Mars year. During perihelion, when
Mars is closest to the sun (summer in the southern hemisphere), the planet
receives 40 percent more sunlight than during aphelion, when it is farthest
from the sun (summer in the northern hemisphere). This annual variation in
sunlight causes 35-degree Fahrenheit increases during southern summer
(perihelion), forcing continental-scale dust storms at the planet's surface.
The dust is swept aloft to altitudes of tens of miles, where it spreads
globally, absorbs light from the sun, and heats the entire atmosphere by
another 30 to 50 degrees Fahrenheit. This dusty perihelion climate was
observed by Viking and Mariner 9 and by NRAO in 1992, 1994, and 1996.

But what the 1970's orbiters did not identify was the very distinctive Mars
aphelion climate, with its planet-wide belts of water ice clouds. These
clouds are as striking as the perihelion global dust storms. During the
aphelion climate, surface dust raised by low dust storms is confined to low
altitudes (about 10 km or 6 miles), and is eventually swept to the ground by
water ice clouds. These clouds surround the planet at altitudes of 3 to 10
km (2 to 6 miles). It is the cold atmospheric conditions of Mars during
aphelion, when the sun is much weaker, that stimulate the formation of these
water ice clouds. The clouds further reduce atmospheric temperatures by
forming around the dust. Without sunlight, the dust freezes and falls to the
ground. This strong competition between dust heating and cloud cooling
drives sweeping annual and short-term regional changes in Mars' climate.
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Attachment #2: Mars Workshop Announcement:
-----------------------------------------------------------------
To: Mars Observing Community
From: Jim Bell, Ann Sprague
Re: Second Synodic Mars Telescopic Observing Workshop

May 15, 1997

Mars Telescopic Workshop 2:

The second Mars Telescopic Workshop is planned for October 2-3, 1997
at the Starr Pass in the Tucson Mtn. foothills.  This gathering of
professional and amateur Mars observers will be similar to the
successful 1995 Mars Telescopic Observations Workshop held in Ithaca, NY.
There are many important goals for the meeting:

* This workshop will provide the first opportunity for Mars telescopic 
observers to synthesize the results gleaned from the 1996-97 apparition
with the results recently obtained from the Pathfinder primary mission
(to be completed in August).

* It will also provide a chance to review synergistic Pathfinder
and ground-based observations and bring together observers
and mission scientists for useful discussion a structured yet
informal setting. 
 
* The meeting will provide the opportunity for the Earth-based community 
to provide a consensus determination of the "state of Mars" prior to the
global mapping by the Mars Global Surveyor mission that will commence
in early 1998. This includes dust opacity, water vapor history, cloud
activity, and surface composition.

* We can continue to explore the theme of short-term climate change by
comparing the results from the 1996-97 (and 1994-95) aphelic apparitions
with those from earlier groundbased and spacecraft measurements. Specifically,
what is the history of dust and atmospheric volatiles during the past few
Mars years examined, and how do these compare with Viking-era data?

* We can continue to forge important links between the professional and
amateur/educational communities by allowing these groups to interact in
a small, focused environment. I think this worked well in Ithaca in 1995.

* As a community, we should work to continually revise the consensus view
of the role of continued groundbased observations, in light of the most
recent spacecraft discoveries and also in light of constantly-evolving
detector and telescope technology.


The program committee will select oral presentations based upon abstracts
submitted with the registration forms.  Participants are encouraged
to submit abstracts on the following topics:

1)  Ground-based (both professional and amateur) and HST 
observations of Mars' surface or atmosphere.  Observations
should be synergistic to or augment planned and future
Mars spacecraft experiments.

2)  Science experiments planned for Pathfinder, Mars Global Surveyor 
or other future Mars Missions that will be enhanced by 
ground-based or HST telescopic observations. 

     There will be informal field trips to local mountain top 
observatories scheduled for Saturday October 4,
on a first-come-first-sign-up basis:

a.  Kitt Peak (Space Watch, 4 m etc.), 
b.  Mt. Hopkins (New Technology etc.)
c.  Mt. Bigelow (Kuiper designed 61 inch planetary telescope)
d.  Mt. Lemmon (several small facilities including lunar coronagraph)


For more information and to receive future mailings about the workshop,
please send email to Jim Bell or Ann Sprague (addresses below) and provide
us with your surface mailing address.  An initial mailing and registration
forms will be sent to you by the Lunar and Planetary Institute.

Conveners:
   Ann Sprague, University of Arizona (sprague@lpl.arizona.edu)
   Jim Bell, Cornell University (jimbo@marswatch.tn.cornell.edu)

Sponsors:
   Lunar and Planetary Institute
   University of Arizona
   Cornell University
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Jim Bell
Cornell University
Department of Astronomy
Center for Radiophysics and Space Research
424 Space Sciences Building
Ithaca, NY 14853-6801
phone: 607-255-5911
fax: 607-255-9002
email: jimbo@marswatch.tn.cornell.edu
WWW: http://marswatch.tn.cornell.edu
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