The Relationships between Climate and River flow in the Alps

The Relationships between Climate and River flow in the Alps

 

(1) Write a brief introduction to the study areas, data etc. (given in table 1), maybe input an annotated map of location?


The study is a presentation of statistical review of patterns in yearly flow records of the Swiss Alps for successive period of 30 years.  The study sets out to determine various significant trends observed at various time series.


(2) Plot the time series of the flows of the two rivers on the same graph, and comment on the pattern of variation shown.


(3) Plot the two river flow series against each other as an xy scattergram. Comment on the distribution.


(4). Plot the histogram of annual total discharge of the Massa, using all the years. Comment on the dispersion shown. To what extent can annual discharge be considered to be normally-distributed?


(5) Calculate the Pearson’s product moment correlation coefficient between the two series. [Choose an empty cell on the spreadsheet – say G1 – and click there. In the text bar type = and then select CORREL from the drop down menu. Correlation coefficients are usually reported to two decimal places. Format cell, number, decimal places 2, enter].

How well are the two series correlated? Are there any periods when the series are not moving in tandem?

 

0.86909. Because the Pearson correlation value is greater than 5% at 0.869. The statistics fails to demonstrate a significant correlation between the two series.

(6) Summer discharge from glacierised basins is likely to fairly strongly influenced by energy availability for melting snow and ice. Plot the xy scattergrams and calculate the correlation coefficients between air temperature and each of the discharge series. Why are both of these values less than 1.0? Add air temperature to the time series graph and add any further comments.


(7) Winter precipitation might affect runoff in summer in two opposing tendencies. In summers following winters with higher than average amounts of snowfall, then runoff might be expected to be enhanced as the additional snow is melted and contributes to runoff. Alternatively, high levels of winter snowfall may retard the rising of the transient snowline, especially when a snowy winter is followed by a cool spring. Such accumulation of snow will reduce the amount of ice melted in summer and hence tend to limit the amount of meltwater entering the discharge. Calculate the correlation coefficients between winter precipitation and each of the discharge series. Plot the xy scattergrams. Why are both of these values fairly close to 0.0? Why are the correlation coefficients negative?

The Correlation coefficient is -0.13788: This therefore demonstrates a strong and positive correlation between the discharge series because the Pearson’s Correlation value is less than 0.005 at -0.13788. Implicitly, winter precipitation has a bearing on the discharge.


(8) Are snowy winters followed by cool summers?
Yes: Summers tend to be cool owing to the cloud cover while winters are milder beyond expectations because of the latitude.

(9) By now sufficient correlation coefficients should have been calculated to produce a matrix of correlation coefficients between all the possible pairs of variables, as below:

Q5-9 Massa Q6-9 Gornera T5-9 Graechen
Q5-9 Massa – – –
Q6-9 Gornera – –
T5-9 Graechen –
P10-5 Graechen

 

  Column 1 Column 2 Column 3 Column 4
Column 1 1
Column 2 0.90565 1
Column 3 0.886126 0.86909 1
Column 4 -0.20826 -0.11811 -0.13788 1

Why are some cells excluded (-)? Complete the table and insert into the document.


(10) Add regression to the graphs produced.

 

SUMMARY OUTPUT
Regression Statistics
Multiple R 0.989195
R Square 0.978507
Adjusted R Square 0.942793
Standard Error 296.1631
Observations 29
ANOVA
  df SS MS F Significance F
Regression 1 1.12E+08 1.12E+08 1274.761 2.91E-24
Residual 28 2455952 87712.58
Total 29 1.14E+08
  Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Lower 95.0% Upper 95.0%
Intercept 0 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
379.05 5.222358 0.146269 35.7038 6.78E-25 4.92274 5.521976 4.92274 5.521976
RESIDUAL OUTPUT PROBABILITY OUTPUT
Observation Predicted 1970 Residuals Standard Residuals Percentile 1970
1 2007.997 -36.9967 -0.12713 1.724138 1971
2 1509.993 462.0074 1.587589 5.172414 1972
3 2059.385 -86.3847 -0.29684 8.62069 1973
4 1650.944 323.0559 1.110112 12.06897 1974
5 1747.401 227.599 0.782095 15.51724 1975
6 1766.619 209.3807 0.719492 18.96552 1976
7 1616.947 360.0535 1.237246 22.41379 1977
8 1432.493 545.5072 1.874518 25.86207 1978
9 1830.071 148.9291 0.511763 29.31034 1979
10 1544.408 435.592 1.496818 32.75862 1980
11 1863.703 117.2971 0.403066 36.2069 1981
12 2250.262 -268.262 -0.92182 39.65517 1982
13 2064.45 -81.4504 -0.27989 43.10345 1983
14 1489.991 494.009 1.697555 46.55172 1984
15 1873.26 111.7402 0.383971 50 1985
16 2034.161 -48.1607 -0.16549 53.44828 1986
17 1969.56 17.43988 0.059928 56.89655 1987
18 2076.201 -88.2007 -0.30308 60.34483 1988
19 2064.868 -75.8682 -0.2607 63.7931 1989
20 2231.148 -241.148 -0.82865 67.24138 1990
21 2218.771 -227.771 -0.78269 70.68966 1991
22 2303.478 -311.478 -1.07033 74.13793 1992
23 2055.729 -62.729 -0.21555 77.58621 1993
24 2591.7 -597.7 -2.05387 81.03448 1994
25 1759.569 235.4309 0.809007 84.48276 1995
26 1672.095 323.9054 1.113031 87.93103 1996
27 1915.874 81.12572 0.278771 91.37931 1997
28 2210.259 -212.259 -0.72938 94.82759 1998
29 2498.272 -499.272 -1.71564 98.27586 1999

 

 


(11) What does the r2 value describe?

The Regression model explains 97.85 percent of the variation of the time series

 


(12) Is the regression line significantly different from one with gradient b=0 ?

 

Yes: The statistics shows that the slope is significantly different from zero,

 

The observed data indicate that the slope is significantly different from zero, thus observed statistics positively indicate that precipitation are largely dependant on various environmental factors

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