Physical Geography - Science topic

In my opinion as a university professor, I think they should hire at least two more geographers. In addition to hydrography, a geomorphologist and biogeographer are necessary (near the Andes, the Pacific coast and rare flora and fauna). As for social geography - spatial planner (especially your National Parks), ethnographer (Mapuche peoples).

Best regards,

Alen Lepirica PhS

Physical geographers indeed study various Earth spheres, focusing on geomorphology, climatology, and biogeography. While their expertise spans multiple disciplines, they generally don't work predominantly in oceanography due to specialization, academic training, research funding and opportunities, distinct research tools, and the natural emphasis on terrestrial processes. Nevertheless, physical geographers often collaborate with oceanographers and other scientists on interdisciplinary projects that explore the interconnectedness of land and sea.

Dear Stabak Roy, many thanks for your answer.

Unfortunately, this is a dead link: https://www.wisar.aewa.org/

Cold you provide a valid URL for this?

Many thanks!

Michael

I recommend this article

Manning's n or roughness coefficient is actually a measure of energy or head loss along a channel reach. The roughness of the channel, bank and floodplain is a major determinant of Manning's n. However, all mechanisms that contribute to energy loss should be considered in selecting its proper value. For example, flow velocity and associated turbulence are important (e.g., if velocity is near zero, the Manning's n will be zero even when the river has high roughness). Similarly flow depth is important. So is the season (e.g., more vegetation and thus higher roughness in summer).

I think engineers should think of Manning's n as more related to energy loss under specific flow conditions than to only roughness.

Sorry, both tests yield a very sign. effect of Location, a rather sign. effect of treatment, but no interaction.

Robust test:

------------------------------value ----------df1 -------- df2 -----------------p.value

Location 113.4956 ------1 ---------100.1808 -------0.0000 treatment 7.0434 -----------1 ----------- 97.6626 ------0.0093

Location:treatment 0.0001 -------1 ---------- 97.6626 ------0.9938

ARTool:

Table Type: Anova Table (Type III tests)

Model: No Repeated Measures (lm)

Response: art(VarX)

----------Df ---Df.res ----------- F value ----------- Pr(>F)

1 treatment --- ---1 326 ---------------4.67749 ----------- 0.031287 *

2 Location ---- 1 326 --------------45.48487 ------------7.0158e-11 ***

3 treatment:Location 1 326 ---------------0.25182 ------------ 0.616132

Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

This may be a different explanation. See https://www.chinasona.org/Thiaoouba/Bermuda-triangle.html

Dear Patrik,

I believe that you have to read in the literature of the science that is related to your field of interest. For example, if you are interested in geomorphology, you will find more applied details in geology books, etc..

Hope this will help.

Best wishes.

Thank you Chandan.

Dear you can visit RG for me ,so I written for this subject and meet to our idea

Not to resurrect an old question but the answers here are... deeply wrong. I'd be having sharp words with undergrads who turned out these answers.

Point 1: Yes obviously there is a Coriolis force for E-W travel at all latitudes. Look at the equation $\Omega \cross v$. Eastward travel gets pushed up from the Earth's surface, Westward travel pushed down. These forces are invariably pathetic compared to gravity but they do exist.

Point 2: Without using equations, Coriolis is all about reference frames. For classic equator-to-pole travel, as you move away from the equator, the ground under your feet is moving West-to-East more slowly, so unless a force is applied to slow YOUR Westward velocity, you increasingly move west relative to the ground

For East-West travel, consider the Great circle corresponding to your latitude and your personal cartesian axes: North, East,Up. By heading "East" you move on a tangent to the great circle. The ground East of you has some component Downwards by your reference frame (and West ground moves "Upwards"). Thus, relative to the ground you seem to be accelerated Up as you go East and Down as you go West. Thus the Coriolis force we expect from the equation.

If you maintained an Eastward trajectory in your original cartesian frame, you start to have an Upward motion relative to the ground's reference frame and thus we get the third coriolis force direction, where you would appear to move East or West more slowly as your velocity vector is less and less aligned with the motion of the Earth's ground.

Do a targeted search within work by Iris Möller https://www.geog.cam.ac.uk/people/moeller because she has published a lot on this topic.

It is time for someone to do a serious study of these events. Not just one investigator, but many of various disciplines and specialties.

People have already solved the disappearance of dinosaurs, why not these phenomena?

You can use the Getdata software, it could precisely get the point (x,y) from the pollen diagram, then use the data to draw another digital diagram.

AS for physical process please read the following   paper!

Budyko, M.I. The effect of solar radiation variations on the climate

of the Earth. Tellus. 21(5)，611–619 (1969). doi:10.1111/j.2153-3490.

1969.tb00466.x.

Try to read more text on your research work and consult professionals on it.

Look the Links

Its well prepared questionnaire and i have added my response

(: Not from me. If you are using ArcMap you should export raster from it with the checkbox "Use renderer". TIFF will then be displayed correctly.

Dear Sumanta: the question you posed is a very complex one! The supercontinent cycle has been operating since at least the Paleoproterozoic or Neoarchean, assembling and disrupting continental masses, creating -and destroying- orogenic belts and ocean basins, volcanic belts, and the like. So it is unquestionable that such tectonic variarions had a strong influence on past climate, just as they have been doing since the Pangea disruption in the Jurassic. The problem is relatively easy to resolve in Mesozoic terrains, a bit more difficult in Paleozoic, and really a hard one in the Precambrian. Conditions for deposition of evaporitic basins were widespread during the Permian, but also in the Devonian and Proterozoic, where large evaporitic basins are found, also aeolian sandstones are frequent in this very dry period, and in older times too. Climate changes so profound as to be unimaginable to us happened when continental blocks collided to form supercontinents. Pangea was covered possibly by a desert three times larger that the actual Sahara, and by an enormous ice cover in its southern parts. The uplift of the Appalachian-Caledonian belt surely had a profound effect in the climate of this supercontinent and global Earth. Before this, in the Neoproterozoic, the uplift of the world-wide Greenvillian system of orogenic belts, which was probably even higher than the Himalaya and longer than the Andes..., due to the assembly of Rodinia, certainly had a marked influence in atmospheric and oceanic circulation, as to eventually lead he planet to the "Snow-ball Earth" global glaciation, just as the uplift of the Andes and Himalaya has done in more recent times, creating large deserts in South America and Central Asia. The problem in older terrains is the large uncertainties in the relative shape, positions and paleolatitudes adquired by land masses, this is relatively easy to solve during the Jurassic, but increasingly difficult to ascertain in older times. With regards, Sebastian.

Dear Sumanta, you are asking a complex question for which there might be no exact answer today. While in economic literature the statement about temperature growth in the last 100 years by only anthropogenic influence dominates, physicists are still in doubt; see for example https://www.newscientist.com/article/dn11639-climate-myths-the-cooling-after-1940-shows-co2-does-not-cause-warming/ . There exists also a hypothesis about global cooling, but on much larger time scale; see http://isthereglobalcooling.com/ . The graph about global temperature and CO2 dynamics is the last 450,000 years is attached (from this source). If this graph is correct, we have an interesting observation: warming went faster (about 10,000 years) than cooling (100,000 years). It is unclear whether triggering is caused by some shocks or some mechanism of dynamic equilibrium on the Earth. But is is also clear that we observe anthropogenic contribution to this process for the 1st time.

The problem however is that we cannot wait too long without making actions to combat global warming. Less carbon emissions would indeed work towards speed reduction of this process, but it might happen that other greenhouse gases (like methane) will continue working in its favor while increase of volcanic activity (observed in the last 10 years) will work towards reduction.

As for the rise of ocean level, the effect is still small today, and is caused not so much by ice melting but more by change of water density with temperature and salinity. However, melting of all Antarctic ice will cause a catastrophic rise of the ocean level by 60 meters; see https://nsidc.org/cryosphere/quickfacts/icesheets.html . Melting of Greenland will have much lower effect (6 meters), but here we observe catastrophic melting in the last years.

Please be concentrated towards remote sensing data for precipitation measurement in a mountain belt latitudinal and longitudinal to reach the conclusion.

If we could take a 'flat land' as a given surface unit area with low variance in altitude range (expressed by DEM pixel values), I'd simply aggregate that DEM to a given factor using a variance function. Establish a threshold and reclass your 1st raster. This could be achieved using R.

I don't work for Nasa, but the latest news- from news bulletins - is that the 2036 encounter would be safe, but there will be some effects by the close encounter of 2029. If some people know more, they will not say in public.

The recent revision of the genus Aphonopelma will give you most of the data you need, certainly the best data available before you seek to add records and distributional data for any of the species..

For up-to-date instrumental seismicity www.gii.co.il

For preinstrumental see Agnon 2014, in Springer Dead Sea Transform book (edited by Garfunkel, Ben-Avraham, Kagan)

DOI 10.1007/978-94-017-8872-4_8

You can check out the attached MSc Project of M.W. Esther. She has used ILWIS 3.3 to derive the LS factor of 'RUSLE'. There are other tutorials which you might find helpful via the ITC website. Links are attached. 

Hi Tofigh,  I am not an expert in this process, but doing spatial analysis all comes down to similar problems-missing data. Would using the average of both controls work?

Dear All..

is it possible to calculate potential area (reserve) with gravity ?

Thanks

 Dear Tielidze, Thanks, it is a nice map. 

You can access the page of Landslides of the USGS, they have many publications of problems and solutions:

And I attached to you an interesting paper about the theme. 

I am not fully aware about rockwork. Rockwork software may be useful for this analysis

Zone-to-Zone Extension accuracies are dependent on the derivative power employed by the transformation software.  Most software packages have truncations of the infinite series at the 7th derivative.  The U.S. Army had Extension Tables truncated at the 14th derivative and had/has accuracies better than 3 millimeters (Forward and Inverse) at plus or minus 45 degrees from the Central Meridian.  ESRI implemented the closed-form of the elliptic integrals several years ago, and their transformations are now good to fractions of a millimeter up to plus or minus 89 degrees from the central meridian.  See: (NOAA Technical Report NESS 81. Improved Algorithm for Calculation of UTM and Geodetic Coordinates. Jeff Dozier. Washington, DC. September 1980.)  However, there are numerous "typos" in the equations.

Have a look on my book "ESSAI (version V2) - L’univers pourrait-il être un réseau 3D et la matière ordinaire en être des singularités topologiques ?". You could find some interesting answers!

Another thought I have.

Do you roughly know the thickness of the ice sheet? And how rough is the subglacial DEM and the surface of the ice?

Maybe it would be useful to take the 3D surface into account. There are tools available in ArcMap (or extensions) to calculate first the surface of each cell based on the topography. During the volume calculation you multiply then the surface of the cell by the thickness of the ice instead of using 100x100m. 

This approach could be more accurate depending of the terrain roughness and the relation between thickness and cell size.

Hi Helene,

To convert ellipsoidal height to mean sea level you need a geoid undulations model of the region you are working on. Depending on the required precision, you can use a global model like EGM2008 ondulation data (N). (http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/Und_min1x1_egm2008_isw=82_WGS84_TideFree.gz). You then need to subtract N from the ellipsoidal height (h) to obtain an estimation of the orthometric height (mean sea level, for practical purposes). More info here: http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/egm08_wgs84.html

If you need more precision or data tied to a particular datum (e.g. a national leveling network), you will have to get a "local" geoid undulations model. Not sure where to get it for South Africa. I hope this helps you. Let me know if you have other questions.

Cheers,

Demián

In order to look at more local effects, such as relations between area of snow-cover & the amount of sediment in the snow, it might be worth to make a few Sarre traps, similar to those used to measure sand transport on beaches.

Perhaps snow Sarre traps should be taller with some guy ropes to hold them still... But actual measurements of transport rates and more detailed  analyses of causes for the dust/sand content would be very interesting to see.

Admittedly, it could be rather cold work to collect a good dataset. Those traps need emptying out regularly (10 min- 2 hours on the beach). Let me know if you need a few more suggestions along this line.

Good luck

Did the land cover around the station changed since the 80's? The change in temperature could be related to the change in land cover around the station (e.g. from agricultural land to urban and built-up). In my paper I showed that changes in land cover classes in a grid cell impact the temperature (due to the changes in the heat fluxes), wind speed and precipitation (De Meij and Vinuesa, Impact of SRTM and Corine Land Cover data on meteorological parameters using WRF, Atmos. Res., 2014). I guess that such impact would be visible in a sharp increase in temperature trend line.

Dear Mritunjay,

For Geological, geomorpholocial map contact GSI. For soil please contact NBSSLUP. They publish soil maps and its properties for each state.

Vaibhav

The "equilibrium" of a riverbed can be reached when the Lane equation is satisfied...

There is no straightforward answer to your question, all depends on the sediment conditions in suspension and in the river bed. For instance, when a river is heavily loaded with suspended mud (there is no such thing as a predictable “maximum”), the maximum erosion velocity of a sandy bed is hindered by the reduced penetration velocity of water-mud mixture to dilate of the grain packing necessary for erosion from the bed. On the other hand, a high suspended sediment concentration reduces the difference of the bulk sediment density of the bed with the overlying fluid, which in case of a bed that consists of cohesive material, or silt, may enable large pieces of the bed to be ripped off and carried away with the flow while disintegrating. A nice example of this is the Yellow River (see Van Maren, D.S., Winterwerp, J.C., Wang, Z.Y., Pu, Q. (2009) Suspended sediment dynamics and morphodynamics in the Yellow River, China. Sedimentology, 56 (3), pp. 785-806).

Two issues on this topic: First: yes of course, mainly on the cratons several parts of the fluvial systems follow the structures of the basement; and second: There were several approaches by Italian geomorphologists linking stream order to tectonic activity, e.g. Belisario et al. (1999) stated that linear river courses of a higher order represent older structures and first order rivers younger ones. Ciccacci et al. (1987) assumed that also first order rivers can follow older structures due to their remobilization. However, the mentioned authors worked mainly in Italy in a distinct “younger” environment, but it’s an interesting approach.

Belisario, F., DelMonte, M., Fredi, P., Funiciello, R., Lupia, E., Salvini, P. & Salvini, F. (1999): Azimuthal Analysis of stream orientations to define regional tectonic lines. Z. Geomorph. N.F., Suppl.-Bd. 118: 41-63.

Ciccacci, S., Fredi, P., Lupia Palmieri, E. & Salvini, F. (1987): An approach to the quanti¬tative analysis of the relations between drainage pattern and fracture trend. International geomorphology, Part II: 49-68.

Adjust your time series in the attached file.

One approach is calculating the fractal dimension of the surface. This is a form of roughness. See a classic paper on the topic: http://www.dtic.mil/dtic/tr/fulltext/u2/a129664.pdf - there are many more modern versions of this an even some tool boxes & APIs out there to help.

I'm going to stick my neck out and answer the question in one word. No.

Now to qualify this.

Brian's answer sets you on the right track, with phenomenology as the first step. Can the sensor you are using detect the effect you are looking for? Immediately you need ancillary data, even if it is simply descriptive of the phenomenon.

An approach which can work and may help you, in the way you pose the question is to look at unsupervised classification methods/PCA etc. Does this identify anomalies around your landfill? Now you have anomalies. Nothing more. In some cases you can characterise them using your data, but eventually you are going to need to get onto the ground for some sort of cal/val exercise.

I'm answering this as I have experienced a number of studies where remote sensing has been employed to produce results which look great, while not answering the question which needs to be answered. It's important to guard against this as it is bad for the image of remote sensing.

Haykel, you have asked a question which in many ways highlights the different "world views" of scientists and decision/policy makers. As you point out, decision makers would like to minimize the uncertainty while scientists, especially climate scientists, live with uncertainty. Part of the problem stems from the two communities not always understanding the needs, capabilities, and limitations of each other. In this particular case the problem is compounded since it is uncertainty upon uncertainty - climate projections contain inherent uncertainty and, as you point out, the impact of climate on water resources is also not well understood. Nevertheless the tools that we have available today, mainly global and regional climate models, are much more powerful and useful than simpler statistical methods of extrapolation. As our understanding of the system improves, so will the models, and thereby the uncertainty will be reduced, although it will never be completely eliminated due to the inherent nature of the system. Certain approaches such as multi-model, ensemble projections, or some type of statistical postprocessing of the model results can further reduce the uncertainty. At the same time new approaches in decision making and management need to be developed which are able to account for and deal with the inherent uncertainty. And perhaps most important, a common "language" needs to be developed that will allow scientists and decision makers communicate more effectively.

Hi Ana-Maria:

I think you can use Print Composer tools in QGIS.

look at Extents dialog to configure how to how them. I hope you find it usefull

Thank you once again, Wenceslau. I sent Dr. Neves a message last night, but these contacts in Rondonia may be better able to help me in the time that I have left here. I did not know about Zimpel before, but will try to contact him here. I had intended to talk to UNIR archaeologists, so this provides a more specific person to contact.

Deltaic systems are so dynamic (on a spatio-temporal scale) to a level that it is near impossible to estimate their variations. Further, 5km is too great a distance that may show numerous variations.

Dear Philip Tieh

It's an interesting question, but do not have a definitive answer.

Fox et al (1997) highlights the problem:

D.M. Fox, R.B. Bryan, A.G. Price. 1997. The influence of slope angle on final infiltration rate for interrill conditions. Geoderma, 80(1–2): 181–194. Doi:10.1016/S0016-7061(97)00075-X.

They says: “Despite numerous studies, the relationship between slope angle and infiltration rate remains unclear. Under different experimental conditions, new processes may be introduced which influence the relationship.”

And they comment also:

“The results showed that sealing intensity did not vary with slope angle, and the dominant influence of slope angle on infiltration rate resulted from changes in overland flow depth and surface storage. The results also suggest that small changes in seal hydraulic conductivity with microrelief play an important role in the infiltration process.”

More recently:

O. Ribolzi, J. Patin, L.M. Bresson, K.O. Latsachack, E. Mouche, O. Sengtaheuanghoung, N. Silvera, J.P. Thiébaux, C. Valentin. 2011. Impact of slope gradient on soil surface features and infiltration on steep slopes in northern Laos. Geomorphology, 127(1–2): 53-63. Doi:10.1016/j.geomorph.2010.12.004.

They say: “Three main conclusions can be drawn from this work: (1) high intensity rainfall can rapidly transform soil surface features of steep bare soil; (2) on steeper slopes, the micro-relief tends to form micro-terraces much more pervious and less erodible than the ripple-like roughness that formed on gentler slopes; and (3) there was a more pronounced lowering of the soil surface due to compaction and denser microlayers on gentler slopes. The latter conclusion confirms the hypothesis that higher effective rainfall intensity is responsible for the formation of less permeable erosion crusts under 30% slope gradients while more permeable structural crusts develop under 75% slope gradients.”

And other articles analyzed partial aspects:

S. Assouline, M. Ben-Hur. 2006. Effects of rainfall intensity and slope gradient on the dynamics of interrill erosion during soil surface sealing. CATENA, 66(3):211–220. doi:10.1016/j.catena.2006.02.005

They say: “Soil erosion during rainfall is strongly affected by runoff and slope steepness. “

And:

M. Koulouri, Chr. Giourga. 2007. Land abandonment and slope gradient as key factors of soil erosion in Mediterranean terraced lands. CATENA, 69(3): 274–281

Good luck

Best regards

Ofelia Gutiérrez

Hello, Cres and Krk (Adriatic sea, Croatia) are 405,8 sq. km each. And there is another 6 islands >100 sq. km, all of them fully karstic or mostly (>90%) karstic islands.

Source: Statistical Yearbook 2013, Croatian Bureau of Statistics, http://www.dzs.hr/default_e.htm

A good overview is also the following discussion paper: http://www.cifor.org/publications/pdf_files/Books/BNasi0201.pdf

I would try Jewel Suite software or GRASS GIS functions for volumes.

That your judgement according to the record of two cores can not be revealed in the third one is not to say that's wrong. the third one should be the case very local and interrupted once formed. Then, grain size can be surely used to understand the origin of the deposits.

Well, a point is a very approximative representation of a landslide and will have an uncertainty, that is correct. If you have an idea about the mean size of the landslide bodies you could define the uncertainties of the landslides location represented by a point. Then it is appropriate to generate a buffer around the landslide points according to the uncertainty ( e.g. 20-50 m). After you can use the remaining area (ouside the buffers) for random sampling.Otherwise, even if you have no information of the landslide size you could still try the buffering, but then the buffer distance should be selected carefully. So you would most likely avoid to have landslide points in a non-landslide sample.

But a I have also a question, why are you using points to charcterize landslides from aerial images? What kind of images do you use (in which ground resolution)? What is the expected scale of analysis? Since you generate a sample for non-landslides points I guess you're giong to do a statistical analysis, logistic regression?

I'm asking because, if the resolution of the images allows the direct mapping of the landlide extent I would use polygons instead of points to do that. For high resolution images even a separation into source and deposition areas is recomended, since after you could gain additional information via magnitude-frequency statistics.

Best Regards,

Jewgenij

Dear Tilak,

I have worked a lot in this issue. I have compiled references since geomorphological mapping starts to be used in geomorphologic surveys, data collection and results presentation. I have some reviews but mostly were published in portuguese language. Indeed the last publication on this matter (I didn´t agree with all the ideas in the book) belongs to Jan Otto and Mike Smith (eds.) published by Elsevier "Geomorphological mapping: methods and applications".

But what I can say to you is that there are no standard symbols and legends apply by everybody. That was the aim of the Subcommission on Geomorphological Mapping of the IGU, that started its activity in 1962. Although the work done, namely the publication of the "Manual of Detailed Geomorphological Mapping", edited by Demek, in 1972, establish the modern concept of geomorphologic mapping and represents in our point of view a sort of revolution in the way how geomorphologic studies are done, the "Project of the Unified Key to the Detailed Geomorphological Map of the World" for maps at 1:25 000 and 1:50 000 scales, failed completely its pourpose. The Unified Key was not applied by the different country researcher and we can say that, nowadays, are the objectives of each work, the habits of each researcher and personal conotations about graphic symbols, that prevail.

In my opinion, we are quite far from the adoption of commum methodologies and legends in the survey of landforms, deposits and processes. On the contrary, it seems that the prevailing tendency it's for the diversification of legends and procedures.

Hi Madyan,

These 'old' references might be useful starting points:

Schwarz, T. (1997). Lateritic bauxite in central Germany and implications for Miocene palaeoclimate. Palaeogeography, Palaeoclimatology, Palaeoecology, 129(1), 37-50.

DArgenio B, Mindszenty A(1995) Bauxites and related paleokarst: Tectonic and climatic event markers at regional unconformities. ECLOGAE GEOLOGICAE HELVETIAE 88:(3) 453-499

best wishes,

Zoltan

You could check out the very interesting and thorough research over the last 10 years on braided channel dimensions, evolution and dynamics in some of the world's largest rivers (e.g. South Saskatchewan River, Canada; the Parana etc.) by Gregory H. Sambrook Smith, Philip J. Ashworth, Jim Best and Stuart N. Lane. You could search on Google Scholar, for example. That body of work would give you a good start in establishing the evidence base to test out answers to your question on width and depth of braid channels. They often use GIS, digital elevation models and ground-penetrating radar approaches.

For example, see this recent paper below on the South Saskatchewan River, Canada - and its large reference list too:

"Quantification of the relation between surface morphodynamics and subsurface sedimentological product in sandy braided rivers"

by

Natalie O. Parker1,

Gregory H. Sambrook Smith1,

Philip J. Ashworth2,

James L. Best3,

Stuart N. Lane4,

Ian A. Lunt5,

Christopher J. Simpson6,

Roberte. Thomas7

published in Sedimentology, Volume 60, Issue 3, pages 820–839, April 2013

Hope this helps to get you started!

You may have a look to shapelib (http://shapelib.maptools.org/) or gdal/ogr ( http://www.gdal.org/ ). Shapelib provides a C - API for vector GIS data, and GDAL/OGR a C++ library for both, raster and vector data, rsp., where, as far as I know, the OGR shapfile driver uses shapelib. Depends also on the input format of your raster files (e.g. ASCII grids are quite easy to read), type of classification and coordinate reference system (proj4 library can do conversions and transformations, if needed).

If you are not coding within your own programming projects, you may also consider GRASS or M4SW (see http://www.maptools.org/ ), which contains a couple of command line utilities that might do what you need.

Indeed you can't, but if you can work on the floodplain evolution, you could do some relative dating. If your abandoned channels and the rest of the floodplain is vegetated, you can always used dendrochronology to constrain your chronology.

Hi plz find attached gmd model if u need more in more info regarding gap filling fell free to ask